Answer: B) 24 kmph Explanation: Total time taken = k/40 + 2k/20 hours = 5k/40 = k/8 hours Average speed = 3k/(k/8) = 24 kmph.

Answer: B) 30 mts Explanation: The cow can graze an area of 2826 sq.m i.e it is able to cover area of circle of 2826 sq.m   Therefore, πr2 =2826r2 =(2826×7/22) = 899.18 = 900r = 30 m.   Therefore, the radius of the circle implies the length of the rope = 30 mts.

Answer: C) 70000 Explanation: 112 × 54112 × 1024= 112 × 1000024= 1120000/16 = 70,000.

Answer: D) 3 : 2 Explanation: Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train = 27 x meters, and length of the second train = 17 y meters. (27 x + 17 y) / (x + y) = 23 => 27 x + 17 y = 23 x + 23 y => 4 x = 6 y => x/y = 3/2.

Answer: B) 4 % Explanation: Imension of the duster is assumed as 5x5x7 cm3 Volume of the duster below the water layer= volume of water increased= πxrxrxh = 3.14×52×2.14 ≈ 168 cm3 Total volume of the duster = 5×5×7 = 175 cm3 Percentage of the duster part below the layer = 168×100/175 = 96% Percentage of the duster part above the layer = 4%

Answer: A) 36 kmph Explanation: Let the speed of goods truck be 'p' kmphDistance covered by goods truck in 10hrs (4+6) = Distance covered by other truck in 4 hrs. 10p = 4 x 90p = 36kmph.Therefore, the speed of the goods truck is p = 36 kmph.

Answer: B) 420 Explanation: Given total number of students in the class = 21   So each student will have 20 greeting cards to be send or receive (21 - 1(himself))   Therefore, the total number of greeting cards exchanged by the students = 20 x 21 = 420.

Answer: B) Rs. 2.04 Explanation: Compound Interest for 1 1⁄2 years when interest is compounded yearly = Rs.(5304 - 5000) Amount after 11⁄2 years when interest is compounded half-yearly Compound Interest for 1 1⁄2 years when interest is compounded half-yearly = Rs.(5306.04 - 5000) Difference in the compound interests = (5306.04 - 5000) - (5304 - 5000)= 5306.04 - 5304 = Rs. 2.04