Risa had five times the number of plastic bricks as Ryan. Risa used all her bricks to build 10 identical figurines. Ryan used all his bricks to build 4 identical figurines. Risa used 9 more bricks than Ryan for each figurine. How many bricks did Ryan have?

	Risa	Ryan
Number	10	4
Value	1 u + 9	1 u
Total value	10 u + 90	4 u

Number of plastic bricks that Ryan used for each figurine = 1 u
Number of plastic bricks that Risa used for each figurine = 1 u + 9

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

Number of plastic bricks that Risa had
= 10 x (1 u + 9)
= 10 u + 90

Risa had five times the number of plastic bricks as Ryan.

5 x 4 u = 10 u + 90
20 u = 10 u + 90
20 u - 10 u = 90
10 u = 90

1 u = 90 ÷ 10 = 9

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

Answer(s): 36