Verbal Reasoning - Mental Ability Questions

The sex of A is not known. So. neither (a) nor (b) is definitely true. Clearly, D is the grandmother of A and F. 

We know that, any decimal number when multiplied by the multiples of 10, the decimal point moves to right the number of zeroes in the multiplying number.

For example :: 

0.0410 x 100 = 4.10 (Number of zeros in 100 are 2. So, the decimal point in 0.0410 moves two places to the right and becomes 4.10.)

Similarly, here in the option C) 5.008 x 10^3 kms it makes 5008 kms as the number of zeros in 10^3  i.e,  1000 are 3 and 5.008 becomes 5008.

Here the given expression, 

X2 + X2 is an algebraic expression. Here in this expression the terms are like terms. Now to add them, add their coefficients.

Here in the given expression, the like terms are two X2

Hence, adding their coefficients i.e, 1 + 1 = 2

Therefore, 

X2 + X2 = 2X2.

Let R, G and B represent the number of balls in red, green and blue boxes respectively.

Then, .

R + G + B = 108 ...(i),

G + R = 2B ...(ii)

B = 2R ...(iii)

From (ii) and (iii), we have G + R = 2x 2R = 4R or G = 3R.

Putting G = 3R and B = 2R in (i), we get:

R + 3R + 2R = 108 6R = 108 R = 18.

Therefore Number of balls in green box = G = 3R = (3 x 18) = 54.