Question

MEDAL AWARD

A cube has an edge which is 4 inches long. If the edge is increased by 25% then the volume is increased by approximately:

(a) 25%
(b) 48%
(c) 73%
(d) 97%
(E)122%

Answer 1

Let:

V1 = original volume
V2 = new volume
S1 = original side length
S2 = new side length

S1 = 4 in
V1 = length x width x height
= 4 x 4 x 4
= 64 cubic inches

S2 = [4 + (.25)4] in
= (4 + 1) in
= 5 in
V2 = 5 x 5 x 5
= 125 cubic inches

64 + 64(97%) = 126.08 cubic inches

The volume increased by approximately 97%.

Answer 2

Oh. Thank you!