Quantitative Aptitude - Arithmetic Ability Questions

I=(p x r x t)/100

Ratio of times taken by A and B = 160 : 100
A can do the work in 12 days
Let B can do the work in "D" days
=> 160:100 = 12 : D
=> D = 12 x 100/160 = 7.5 hrs

It takes four of those little squares -- each one 1/2 inch on a side -- to cover one square inch. That's because each one is 1/2 x 1/2, or 1/4 of a square inch.
In a rectangle that is 48 inches by 48 inches, there are 2304 square inches.(1 ft = 12 inches)
Since it takes 4 little squares to cover 1 sq inch, then it would need 2304 x 4 squares (1/2 inch on a side each) to cover a rectangle 4 feet by 4 feet.

That is 9,216 of those squares.

Given 0.875 and 0.375

0.875 ::

After decimal point there are 3 digits 875

Now, mutiply and divide 0.875 with 1000

$$\begin{gathered} 0.875 x 10001000 = 8751000 \\ Now, this can be reduced to fraction 78 \\ Therefore, 0.875 as fraction = 78 \end{gathered}$$

Similarly,

0.375 :: 

After decimal point there are 3 digits 375

Now, mutiply and divide 0.375 with 1000

$$\begin{gathered} 0.375 x 10001000 = 3751000 \\ Now, this can be reduced to fraction 38 \\ Therefore, 0.375 as fraction = 38 \end{gathered}$$

L.C.M. of 252, 308 and 198 = 2772.

So, A, B and C will again meet at the starting point in 2772 sec. i.e., 46 min. 12 sec.

We know that, M1 × D1W1 = M2 × D2W2

Here M1 = 1, D1 = 6 min, W1 = 1 and M2 = M, D2 = 90 min, W2 = 1845

1 × 61 = M × 901845 

=> M = 123

We know, 

S.I = PTR/100 where P = principal amount, T = time, R = rate of interest

Here in the given data,

Interest for two years S.I = 924 - 812 = Rs. 112

Now, Principal amount P = 812 - 112 = Rs. 700 

Now,

R = S.I x 100/PT

R = 112 x 100/700 x 2

R = 11200/1400

R = 8%

Hence, the rate of interest R = 8%.