Quantitative Aptitude Answer With Explanation For Bank Exam

1.The average age of a man and his son is 44 years.The ratio of their ages is 31:13 respectively.What is the son's age?
[1]35 years   [2]26 years  [3]15 years   [4]20 years   [5]None of these

2.A car travels at an average of 50 miles per hour for 2 1/2 hours and then travels at a speed of 70 miles per hour for 1 1/2 hours. How far did the car travel in the entire 4 hours?

[1]. 210 miles
[2]. 230 miles
[3]. 250 miles
[4]. 260 miles
[5]None of these

3.What would be the simple interest obtained on an amount of Rs.64728 at the rate of 10 p.c.p.a. after 7 years?
[1]Rs.45309.6
[2]Rs.39214.2
[3]Rs.48077.5
[4]Rs.40223.1
[5]None of these.

4.A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
[1].4
[2] 5
[3]6
[4]10
[5]7   

5.What is the least number to be added to 2600 to make it a perfect square?
[1]1
[2]5
[3]3
[4]9
[5] None of these.


Answer1.[2]Let the man's age be 31x years and that of his son be 13x years.
According to the question,
31x  + 13x  = 2*44

=>44x = 88 => 88/44 = 2
Son's age = 13x
= 13*2 = 26 years

2.[2]Speed[1] = 50 miles/hour    Time[1]= 2 1/2  hour = 5/2 hour
 =>Distance1 = Speed1 × Time1 = 50×5/2=25×5=125 miles
Speed[2] = 70 miles/hour    Time[2] = 1 1/2 hour = 3/2 hour
Distance[2] = Speed2 × Time2 = 70×3/2=35×3=105 miles
Total Distance = Distance1 + Distance2 =125+105=230 miles

3.[1]SI= P*R*T
              100

           = 64728 * 10 *7
                       100
      = Rs. 45309.6     
4[2].Let the speed of the stream be x km/hr. Then,

Speed downstream = (15 + x) km/hr,

Speed upstream = (15 - x) km/hr.

   
  30       +             30         =  4 1/2
(15 + x)        (15 - x)

900             =   9
225 - x2           2

9x2 = 225

x2 = 25

x = 5 km/hr.        

5[1]50 *50 = 2500
51 *51 = 2600
Least  number to be added
= 2601 - 2600  =1