Answer: B) 7 hrs Explanation: Given, P can fill in 12 hrs Q can fill in 15 hrs R can fill in 20 hrs => Volume of tank = LCM of 12, 15, 20 = 60 lit => P alone can fill the tank in 60/12 = 5 hrs => Q alone can fill the tank in 60/15 = 4 hrs => R alone can fill the tank in 60/20 = 3 hrs Tank can be filled in the way that (P+Q) + (P+R) + (P+Q) + (P+R) + .... => Tank filled in 2 hrs = (5+4) + (5+3) = 9 + 8 = 17 lit => In 6 hrs = 17 x 6/2 = 51 lit => In 7th hr = 51 + (5+4) = 51 + 9 = 60 lit => So, total tank will be filled in 7 hrs.

Answer: B) स्ट्रोंटियम व्याख्या: हम जानते हैं कि आवर्त सारणी के एक ही समूह के तत्वों में समान विशेषताएं होती हैं। यहाँ मैग्नीशियम और स्ट्रोंटियम ने कुछ समान गुण साझा किए क्योंकि वे दोनों एक ही समूह के हैं। Sr स्ट्रोंटियम का रासायनिक प्रतीक है जो एक समूह दो तत्व है; इसका परमाणु क्रमांक 38 है।

Answer: D) 9:1 Explanation: Milk = 3/5 x 20 = 12 liters, water = 8 liters   If 10 liters of mixture are removed, amount of milk removed = 6 liters and amount of water removed = 4 liters.   Remaining milk = 12 - 6 = 6 liters Remaining water = 8 - 4 = 4 liters   10 liters of pure milk are added, therefore total milk = (6 + 10) = 16 liters.   The ratio of milk and water in the new mixture = 16:4 = 4:1   If the process is repeated one more time and 10 liters of the mixture are removed, then amount of milk removed = 4/5 x 10 = 8 liters.   Amount of water removed = 2 liters.   Remaining milk = (16 - 8) = 8 liters. Remaining water = (4 -2) = 2 liters.   Now 10 lts milk is added => total milk = 18 lts   The required ratio of milk and water in the final mixture obtained   = (8 + 10):2 = 18:2 = 9:1.

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

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

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.

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!

Answer: D) 15 Explanation: We know M1×D1×H1W1 = M2×D2×H2W2    => 15×4×1435 = M×8×1050   => M = 15