Answer: B) 50 Explanation: Sony and her brother's age sum is 31Let Sony's mother's age be 'x'.Now the conditions given for both of their ages related to their mom is1/5(x-15) + 3/5(x-10) = 31x-15 + 3x-30 = 1554x-45 = 1554x = 200x = 50So, Mother's age = 50. Cross verification : 15 years ago age = 35 => Sony age = 710 years ago age = 40 => bro age = 24 Sum = 24 + 7 = 31.

Answer: B) 420 m Explanation: Let the length of the stationary train Y be LY Given that length of train X, LX = 300 m Let the speed of Train X be V. Since the train X crosses train Y and a pole in 60 seconds and 25 seconds respectively. => 300/V = 25 ---> ( 1 ) (300 + LY) / V = 60 ---> ( 2 ) From (1) V = 300/25 = 12 m/sec. From (2) (300 + LY)/12 = 60 => 300 + LY = 60 (12) = 720 => LY = 720 - 300 = 420 m Length of the stationary train = 420 m

Answer: B) Rs. 2200 Explanation: He sold 4 cycles for Rs. 8400[It means each cycle price is Rs. 2100]And again he sold 3 cycles for Rs. 1900 eachIf he want to gain avg profit on each cycle is Rs. 320 per cycle.So profit for 10 cycles is @ Rs.320 is,10 x 320 = Rs. 3200He already got Rs. 1850 profit by selling 7 cycles.Now, remaining amount is 3200 - 1850 = 1350So from remaining 3 cycles we want to get Rs. 1350 profit ,1350/3 = 450so he must sell remaining 3 cycles at Rs. 2200 each one.

Answer: D) 70 kmph Explanation: By car 240 km at 60 kmphTime taken = 240/60 = 4 hr. By train 240 km at 60 kmphTime taken = 400/100 = 4 hr. By bus 240 km at 60 kmphTime taken = 200/50 = 4 hr. So total time = 4 + 4 + 4 = 12 hr. and total speed = 240+400+200 = 840 kmAverage speed of the whole journey = 840/12 = 70 kmph.

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Answer: D) 144 Explanation: Given ratio of pens and pencils = 3 :2 Number of Pens = 3x Number of Pencils = 2x Average number of pencils & Pens = 3x + 2x2 = 180 5x = 360 => x = 72 Hence, the number of pencils = 2x = 72 x 2 = 144.

Answer: C) 2 Explanation: Let work done by 1 man in i day be m and Let work done by 1 boy in 1 day be b From the given data, 4(5m + 3b) = 23 20m + 12b = 23....(1) 2(3m + 2b) = 7 6m + 4b = 7 ....(2) By solving (1) & (2), we get m = 1, b = 1/4 Let the number of required boys = n 6(7 1 + n x 1/4) = 45 => n = 2.

Answer: D) 165 Explanation: Ratio C1:C2 = 3:5 and C2:C3 = 7:11So C1:C2:C3 = 21 : 35 : 55Let the strength of three classes are 21x, 35x and 55x respectively, then Given that 21x + 35x + 55x = 333=> 111x = 333 or x=3So strength of the class with highest number of students =55x = 55x3 = 165.