Tiffany had five times the number of metallic blocks as Riordan. Tiffany used all her blocks to build 10 identical cars. Riordan used all his blocks to build 4 identical cars. Tiffany used 9 more blocks than Riordan for each car. How many blocks did Riordan have?

	Tiffany	Riordan
Number	10	4
Value	1 u + 9	1 u
Total value	10 u + 90	4 u

Number of metallic blocks that Riordan used for each car = 1 u
Number of metallic blocks that Tiffany used for each car = 1 u + 9

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

Number of metallic blocks that Tiffany had
= 10 x (1 u + 9)
= 10 u + 90

Tiffany had five times the number of metallic blocks as Riordan.

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 blocks that Riordan had
= 4 u
= 4 x 9
= 36

Answer(s): 36