A is 4 times as heavy as B. B is half the weight of C. C is 2 . 5...

According to the question,

A $= 4$B

B $= \dfrac{C}{2}$

C $= 2 . 5 \times$D

D $= \dfrac{1}{4} \times$E

A : B $= 4: 1 = 20: 5$

B : C $= 1: 2 = 5: 10$

C : D $= 5: 2 = 10: 4$

D : E $= 1: 4 = 4: 16$

So,

A : B : C : D : E $= 20: 5: 10: 4: 16$

From this ratio, it is clear that A is the heaviest.