Quantitative Aptitude - Arithmetic Ability Questions

12 men120 acres36 days54 men?54 days

 As 12 men can reap 120 acres, 54 men will be able to reap more acres in 36 days, 120 acres of land was reaped, so in 54 days, more land will be reaped.

Thus, the numbers of acres that can be reaped by 54 men in 54 days = 5412x120x5436 = 810 acres

Let Hari Ram's present age = x

Then, his son's age = x/3

Father's age = 5x/2

$$\begin{gathered} x + x3 + 52x3 = 46 \\ => x = 36 yrs \end{gathered}$$

Now the required difference = 52x36 - 363 = 78 yrs

Let the number of bricks be 'N'

10 x 4/100 x 6 x 90/100 = 25/100 x 15/100 x 8/100 x N

10 x 4 x 6 x 90 = 15 x 2 x N => N = 720.

Walking at 3/4th of usual rate implies that time taken would be 4/3th of the usual time. In other words, the time taken is 1/3rd more than his usual time

so 1/3rd of the usual time = 15min
or usual time = 3 x 15 = 45min = 45/60 hrs = 3/4 hrs.

Let the speed of boat and stream be x and y kmph respectively.

According to question

d/x+y + d/x-y = 5h 15m or 21/4 hrs ......(i)

and 2d/x-y = 7...... (ii)

From eq. (i) and (ii)

2d/x+y = 7/2

Hence, Amith will take to row 2d km distance downstream in 7/2 hrs

= 3.5 hrs

= 3 hrs 30 min.

Given A alone can fill the tank of capacity 240 lit in 16 hrs.

=> A can fill in 1 hr = 240/16 = 15 lit

=> B alone can fill the tank of capacity 240 lit in 12 hrs.

=> B can fill in 1 hr = 240/12 = 20 lit

Now, (A + B) in 1 hr = 15 + 20 = 35 lit

But they are opened for 2 hrs

=> 2 x 35 = 70 lit rae filled

Remaining water to be filled in tank of 240 lit = 240 - 70 = 170 lit.

Ratio of efficiency of A to B is 3 : 2

Let, In 8 days they complete = (3 + 2) × 8 = 40 units

So, total work = 40 × 12/5 units

Time taken by B alone to complete whole work = 40 ×  12/5 ×2 = 48 days 

Let the principle be Rs. P
As the amount double itself the interest is Rs. P too
So P = P x r x 15/100
=> r = 100/15 = 20/3 % = 6.66 %.