Quantitative Aptitude - Arithmetic Ability Questions

Speed of the Train K is given by s = d/t = 240/20 = 12 m/s
Distance covered by Train K in 50 seconds = 12 x 50 = 600 mts.
But it crosses Train L in 50 seconds
Therefore, the length of the Train L is = 600 - 240 = 360 mts.

Except 437 all others are prime numbers.

Speed in still water = Average of Speed in Upstream and speed in Downstream

= 1/2 (12 + 6) kmph = 9 kmph.

Given that 3x-y=27, 3x+y=243

⇒3x-y =33 , 3x+y=35

 => x-y=3, x+y=5

 => x = 4

Taking the 2 investments to be 3x and 5x respectively
Total income of Raghu = (3x) x 1.25 + (5x) x 0.9 = 8.25
Therefore, Gain% = 0.25/8 x 100 = 3.125 %.

Given the price of a commodity is decreased by  p = 20%

And its consumption is increased by q = 10%

Now, required increase or decrease in the expenditure on the commodity can be 

p + q + pq/100 = -20 + 10 - 200/100 = -10 - 2 = -12%.

Hence, decrease in the expenditure = 12%

Let the rate be R% p.a.

I  gives, P = Rs. 8000 and T = 4 years.

II gives, S.I = Rs. (8800 - 8000) = Rs. 800.

R = [100 x S.I] / [p x t ]= (100 x 800)/(8000 x 4) = 2 ½ % p.a

Thus, I and II both are needed to get the answer.

Days remaining 124 – 64 = 60 days

Remaining work = 1 - 2/3 = 1/3

Let men required men for working remaining days be 'm'

So men required = (120 x 64)/2 = (m x 60)/1 => m = 64

Men discharge = 120 – 64 = 56 men.