Question

If B is 10% heavier than A and C is 10% lighter than B, then what can you say about the relative weights of A and C?

Answer 1

Let Weight of A = x

Then

weight of B = x + 10x/100 = x + x/10 = 11x/10

And C is 10% lighter than B means,

Weight of C = 11x/10 - 10% of 11x/10 = 11x/10 - 11x/10×10/100 = 11x/10 - 11x/100 = 110x − 11x / 100 = 99x/100

Now if we add 1 % weight of A in C weight we get

99x/100 + x/100 = 100x/100 = x ( weight of A )

So, we can say that

C is 1% lighter than A .