Jade had thrice the number of metallic blocks as Charlie. Jade used all her blocks to build 8 identical cars. Charlie used all his blocks to build 4 identical cars. Jade used 9 more blocks than Charlie for each car. How many blocks did Charlie have?

	Jade	Charlie
Number	8	4
Value	1 u + 9	1 u
Total value	8 u + 72	4 u

Number of metallic blocks that Charlie used for each car = 1 u
Number of metallic blocks that Jade used for each car = 1 u + 9

Number of metallic blocks that Charlie had
= 4 x 1 u
= 4 u

Number of metallic blocks that Jade had
= 8 x (1 u + 9)
= 8 u + 72

Jade had thrice the number of metallic blocks as Charlie.

3 x 4 u = 8 u + 72
12 u = 8 u + 72
12 u - 8 u = 72
4 u = 72

1 u = 72 ÷ 4 = 18

Number of blocks that Charlie had
= 4 u
= 4 x 18
= 72

Answer(s): 72