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प्र: The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years and that of the girls is 15.4 years. What is the ratio of boys to girls in the class ? 1281 0

उत्तर : 2. "2:3"
व्याख्या :
Answer: B) 2:3 Explanation: Let number of boys = x , Let number of girls = yTotal numbers of students = x + y(x + y) × 15.8 = 16.4x + 15.4y 0.6x = 0.4yx/y = 0.4/0.6 = 2/3 Ratio of boys and girls in the class is 2:3

प्र: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 3603 0

उत्तर : 2. "30 years"
व्याख्या :
Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

प्र: Pipe K fills a tank in 30 minutes. Pipe L can fill the same tank 5 times as fast as pipe K. If both the pipes were kept open when the tank is empty, how much time will it take for the tank to overflow ? 2982 0

उत्तर : 4. "5 minutes"
व्याख्या :
Answer: D) 5 minutes Explanation: Let the total capacity of tank be 90 liters.Capacity of tank filled in 1 minute by K = 3 liters.Capacity of tank filled in 1 minute by L = 15 liters.Therefore, capacity of the tank filled by both K and L in 1 minute = 18 liters.Hence, time taken by both the pipes to overflow the tank = 90/18 = 5 minutes.

प्र: Without any stoppage, a person travels a certain distance at an average speed of 42 km/h, and with stoppages he covers the same distance at an average speed of 28 km/h. How many minutes per hour does he stop? 5945 0

उत्तर : 2. "20 minutes"
व्याख्या :
Answer: B) 20 minutes Explanation: Let the total distance to be covered is 84 kms.Time taken to cover the distance without stoppage = 84/42 hrs = 2 hrsTime taken to cover the distance with stoppage = 84/28 = 3 hrs.Thus, he takes 60 minutes to cover the same distance with stoppage.Therefore, in 1 hour he stops for 20 minutes.

प्र: One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture. 1979 0

उत्तर : 1. "27 %"
व्याख्या :
Answer: A) 27 % Explanation: Let the percentage of benzene = X(30 - X)/(X- 25) = 6/4 = 3/2 => 5X = 135 X = 27 So, required percentage of benzene = 27 %

प्र: If the selling price of a mat is five times the discount offered and if the percentage of discount is equal to the percentage profit, find the ratio of the discount offered to the cost price. 3935 0

उत्तर : 3. "7:30"
व्याख्या :
Answer: C) 7:30 Explanation: Since S.P. = 5 (M.P. - S.P.) => 5 M.P. = 6 S.P.M.P. = (6/5) S.P.Since the percentage discount = Percentage profit,65S.P - S.P65S.P×100 = S.P -C.PC.P×100Therefore, 1/6 = (S.P/C.P) – 1 => S.P = (7/6) C.PM.P = 6/5 S.P = 6/5 x 7/6 C.P = 7/5 C.PTherefore, Ratio of discount to C.P= (M.P – S.P)/C.P = [{(7/5)C.P - (7/6)C.P} / C.P.]= 7/30 Therefore, the ratio is 7 : 30

प्र: Three maths classes: A, B and C take an algebra test. The average score of class A is 83. The average score of class B is 76. The average score of class C is 85. The average score of class A and B is 79 and average score of class B and C is 81. What is the average score of classes A, B, C ? 1408 0

उत्तर : 4. "81.5"
व्याख्या :
Answer: D) 81.5 Explanation: Let the number of students in classes A, B and C be P, Q and R respectively.Then, total score of A = 83P, total score of B = 76Q, total score of C = 85R.Also given that,(83P + 76Q) / (P + Q) = 79=>4P = 3Q.(76Q + 85R)/(Q + R) = 81=>4R = 5Q,=>Q = 4P/3 and R = 5P/3Therefore, average score of A, B, C = ( 83P + 76Q + 85R ) / (P + Q + R) = 978/12 = 81.5

प्र: 'A' sold an article to 'B' at a profit of 20%. 'B' sold the same article to 'C' at a loss of 25% and 'C' sold the same article to 'D' at a profit of 40%. If 'D' paid Rs 252 for the article, then find how much did 'A' pay for it? 2166 0

उत्तर : 3. "Rs.200"
व्याख्या :
Answer: C) Rs.200 Explanation: Let the article costs 'X' to ACost price of B = 1.2XCost price of C = 0.75(1.2X) = 0.9XCost price of D = 1.4(0.9X) = 1.26X = 252Amount paid by A for the article = Rs. 200.

प्र: The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years and that of the girls is 15.4 years. What is the ratio of boys to girls in the class ? 1281 0

उत्तर : 2. "2:3"
व्याख्या :
Answer: B) 2:3 Explanation: Let number of boys = x , Let number of girls = yTotal numbers of students = x + y(x + y) × 15.8 = 16.4x + 15.4y 0.6x = 0.4yx/y = 0.4/0.6 = 2/3 Ratio of boys and girls in the class is 2:3

प्र: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 3603 0

प्र: Pipe K fills a tank in 30 minutes. Pipe L can fill the same tank 5 times as fast as pipe K. If both the pipes were kept open when the tank is empty, how much time will it take for the tank to overflow ? 2982 0

प्र: Without any stoppage, a person travels a certain distance at an average speed of 42 km/h, and with stoppages he covers the same distance at an average speed of 28 km/h. How many minutes per hour does he stop? 5945 0

प्र: One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture. 1979 0

उत्तर : 1. "27 %"
व्याख्या :
Answer: A) 27 % Explanation: Let the percentage of benzene = X(30 - X)/(X- 25) = 6/4 = 3/2 => 5X = 135 X = 27 So, required percentage of benzene = 27 %

प्र: If the selling price of a mat is five times the discount offered and if the percentage of discount is equal to the percentage profit, find the ratio of the discount offered to the cost price. 3935 0

प्र: 'A' sold an article to 'B' at a profit of 20%. 'B' sold the same article to 'C' at a loss of 25% and 'C' sold the same article to 'D' at a profit of 40%. If 'D' paid Rs 252 for the article, then find how much did 'A' pay for it? 2166 0

उत्तर : 3. "Rs.200"
व्याख्या :
Answer: C) Rs.200 Explanation: Let the article costs 'X' to ACost price of B = 1.2XCost price of C = 0.75(1.2X) = 0.9XCost price of D = 1.4(0.9X) = 1.26X = 252Amount paid by A for the article = Rs. 200.

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प्र: The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years and that of the girls is 15.4 years. What is the ratio of boys to girls in the class ? 1281 05b5cc75ee4d2b4197774fcd4

उत्तर : 2. "2:3" व्याख्या :Answer: B) 2:3 Explanation: Let number of boys = x , Let number of girls = yTotal numbers of students = x + y(x + y) × 15.8 = 16.4x + 15.4y 0.6x = 0.4yx/y = 0.4/0.6 = 2/3 Ratio of boys and girls in the class is 2:3

प्र: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 3603 05b5cc75ee4d2b4197774fcca

प्र: Pipe K fills a tank in 30 minutes. Pipe L can fill the same tank 5 times as fast as pipe K. If both the pipes were kept open when the tank is empty, how much time will it take for the tank to overflow ? 2982 05b5cc75ee4d2b4197774fcc5

प्र: Without any stoppage, a person travels a certain distance at an average speed of 42 km/h, and with stoppages he covers the same distance at an average speed of 28 km/h. How many minutes per hour does he stop? 5945 05b5cc75ee4d2b4197774fcbb

प्र: One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture. 1979 05b5cc75ee4d2b4197774fcc0

उत्तर : 1. "27 %" व्याख्या :Answer: A) 27 % Explanation: Let the percentage of benzene = X(30 - X)/(X- 25) = 6/4 = 3/2 => 5X = 135 X = 27 So, required percentage of benzene = 27 %

प्र: If the selling price of a mat is five times the discount offered and if the percentage of discount is equal to the percentage profit, find the ratio of the discount offered to the cost price. 3935 05b5cc75ee4d2b4197774fcb1

प्र: 'A' sold an article to 'B' at a profit of 20%. 'B' sold the same article to 'C' at a loss of 25% and 'C' sold the same article to 'D' at a profit of 40%. If 'D' paid Rs 252 for the article, then find how much did 'A' pay for it? 2166 05b5cc75ee4d2b4197774fca2

उत्तर : 3. "Rs.200" व्याख्या :Answer: C) Rs.200 Explanation: Let the article costs 'X' to ACost price of B = 1.2XCost price of C = 0.75(1.2X) = 0.9XCost price of D = 1.4(0.9X) = 1.26X = 252Amount paid by A for the article = Rs. 200.

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प्र: The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years and that of the girls is 15.4 years. What is the ratio of boys to girls in the class ? 1281 0

उत्तर : 2. "2:3"
व्याख्या :
Answer: B) 2:3 Explanation: Let number of boys = x , Let number of girls = yTotal numbers of students = x + y(x + y) × 15.8 = 16.4x + 15.4y 0.6x = 0.4yx/y = 0.4/0.6 = 2/3 Ratio of boys and girls in the class is 2:3

प्र: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 3603 0

प्र: Pipe K fills a tank in 30 minutes. Pipe L can fill the same tank 5 times as fast as pipe K. If both the pipes were kept open when the tank is empty, how much time will it take for the tank to overflow ? 2982 0

प्र: Without any stoppage, a person travels a certain distance at an average speed of 42 km/h, and with stoppages he covers the same distance at an average speed of 28 km/h. How many minutes per hour does he stop? 5945 0

प्र: One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture. 1979 0

उत्तर : 1. "27 %"
व्याख्या :
Answer: A) 27 % Explanation: Let the percentage of benzene = X(30 - X)/(X- 25) = 6/4 = 3/2 => 5X = 135 X = 27 So, required percentage of benzene = 27 %

प्र: If the selling price of a mat is five times the discount offered and if the percentage of discount is equal to the percentage profit, find the ratio of the discount offered to the cost price. 3935 0

प्र: 'A' sold an article to 'B' at a profit of 20%. 'B' sold the same article to 'C' at a loss of 25% and 'C' sold the same article to 'D' at a profit of 40%. If 'D' paid Rs 252 for the article, then find how much did 'A' pay for it? 2166 0

उत्तर : 3. "Rs.200"
व्याख्या :
Answer: C) Rs.200 Explanation: Let the article costs 'X' to ACost price of B = 1.2XCost price of C = 0.75(1.2X) = 0.9XCost price of D = 1.4(0.9X) = 1.26X = 252Amount paid by A for the article = Rs. 200.