Usha had four times the number of plastic bricks as Oliver. Usha used all her bricks to build 8 identical ships. Oliver used all his bricks to build 4 identical ships. Usha used 9 more bricks than Oliver for each ship. How many bricks did Oliver have?

	Usha	Oliver
Number	8	4
Value	1 u + 9	1 u
Total value	8 u + 72	4 u

Number of plastic bricks that Oliver used for each ship = 1 u
Number of plastic bricks that Usha used for each ship = 1 u + 9

Number of plastic bricks that Oliver had
= 4 x 1 u
= 4 u

Number of plastic bricks that Usha had
= 8 x (1 u + 9)
= 8 u + 72

Usha had four times the number of plastic bricks as Oliver.

4 x 4 u = 8 u + 72
16 u = 8 u + 72
16 u - 8 u = 72
8 u = 72

1 u = 72 ÷ 8 = 9

Number of bricks that Oliver had
= 4 u
= 4 x 9
= 36

Answer(s): 36