IIT JEE Practice Question and Answer
8Q: The average age of a couple and their son was 40 years, the son got married and a child was born just two years after their marriage. When child turned to 10 years, then the average age of the family becomes 38 years. What was the age of the daughter in law at the time of marriage ? 2743 05b5cc6c6e4d2b4197774de59
5b5cc6c6e4d2b4197774de59- 112 yearstrue
- 210 yearsfalse
- 314 yearsfalse
- 413 yearsfalse
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Answer : 1. "12 years"
Explanation :
Answer: A) 12 years Explanation: Given the average age of couple and their son = 40 => Sum of age (H +W +S) = 40×3 Let the age of daughter in law at the time of marriage = D years Now after 10 years, (H + S +W) + 3×12 + D +12 + 10 = 38×5 178 + D = 190 D = 190 -178 = 12 years
Q: How many parallelograms will be formed if 7 parallel horizontal lines intersect 6 parallel vertical lines? 2739 05b5cc754e4d2b4197774fbb4
5b5cc754e4d2b4197774fbb4- 1215false
- 2315true
- 3415false
- 4115false
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Answer : 2. "315"
Explanation :
Answer: B) 315 Explanation: Parallelograms are formed when any two pairs of parallel lines (where each pair is not parallel to the other pair) intersect. Hence, the given problem can be considered as selecting pairs of lines from the given 2 sets of parallel lines. Therefore, the total number of parallelograms formed = 7C2 x 6C2 = 315
Q: Tennis rackets and ballpoint pens are 2739 05b5cc60ae4d2b4197774b5ab
5b5cc60ae4d2b4197774b5ab- 1complementary goodsfalse
- 2independent goodstrue
- 3inferior goodsfalse
- 4substitute goodsfalse
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Answer : 2. "independent goods"
Explanation :
Answer: B) independent goods Explanation: Tennis rackets and ballpoint pens are two independent goods. Since, one doesn't depend on the other.
Q: If (1 × 2 × 3 × 4 ........ × n) = n!, then 15! - 14! - 13! is equal to ___? 2738 05b5cc6bee4d2b4197774d997
5b5cc6bee4d2b4197774d997- 114 × 13 × 13!false
- 215 × 14 × 14!false
- 314 × 12 × 12!false
- 415 × 13 × 13!true
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Answer : 4. "15 × 13 × 13!"
Explanation :
Answer: D) 15 × 13 × 13! Explanation: 15! - 14! - 13! = (15 × 14 × 13!) - (14 × 13!) - (13!) = 13! (15 × 14 - 14 - 1) = 13! (15 × 14 - 15) = 13! x 15 (14 - 1) = 15 × 13 × 13!
Q: Three men, four women and six children can complete a work in 9 days. A women does double the work a man does and a child does half the work a man does. How many women alone can complete this work in 9 days? 2738 05b5cc6b2e4d2b4197774d374
5b5cc6b2e4d2b4197774d374- 17true
- 28false
- 39false
- 46false
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Answer : 1. "7"
Explanation :
Answer: A) 7 Explanation: Given (3 Men + 4 Women + 6 Children) -----> 9 days But W = 2M and C = M/2 Now, convert Men and Children into Women by 3W2 + 4W + 6W4=> 32 + 4 + 32 = 7 Women Therefore, 7 women alone can complete this work in 9 days.
Q: If 15 men 4 hours per day works for 14 days get Rs.35/- then how many men required if the work is 8 hours per day for 10 days they get 50/- ? 2735 05b5cc754e4d2b4197774fb68
5b5cc754e4d2b4197774fb68- 112false
- 213false
- 314false
- 415true
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Answer : 4. "15"
Explanation :
Answer: D) 15 Explanation: We know M1×D1×H1W1 = M2×D2×H2W2 => 15×4×1435 = M×8×1050 => M = 15
Q: C U B A E D E D A B E B A U C D B C A D B D U B C A C B E D A If all the A's are dropped from the above arrangement, which of the following will be eleventh from the left end of the above arrangement? 2731 05b5cc7d2e4d2b419777512e0
5b5cc7d2e4d2b419777512e0- 1Efalse
- 2Cfalse
- 3Dfalse
- 4Utrue
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Answer : 4. "U"
Explanation :
Answer: D) U Explanation: If all the A's are dropped from the above arrangement, we get C U B E D E D B E B U C D B C D B D U B C C B E D. Here the eleventh from the left end of the above arrangement is U
Q: A rectangular block has the dimensions 5x6x7 cm it is dropped into a cylindrical vessel of radius 6cm and height 10 cm. If the level of the fluid in the cylinder rises by 4 cm, What portion of the block is immersed in the fluid ? 2731 05b5cc70ee4d2b4197774f337
5b5cc70ee4d2b4197774f337- 122/7 x 24/35true
- 222/7 x 36 x 4false
- 322/7 x 36/5false
- 422/7 x 37/21false
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Answer : 1. "22/7 x 24/35"
Explanation :
Answer: A) 22/7 x 24/35 Explanation: Since level of water increased in cylinder by height 4. This is because of the rectangular block . Therefore , area of rectangular block immersed in water is = 227×6×6×4 Thats why portion of block immersed in water is = (22/7 * 36 * 4) / total vol. of rectangle = (22/7 * 36 * 4)/ (7*5*6) = (22/7 * 24)/ 35.