Xuan had four times the number of wooden bricks as Henry. Xuan used all her bricks to build 10 identical cars. Henry used all his bricks to build 4 identical cars. Xuan used 9 more bricks than Henry for each car. How many bricks did Henry have?

	Xuan	Henry
Number	10	4
Value	1 u + 9	1 u
Total value	10 u + 90	4 u

Number of wooden bricks that Henry used for each car = 1 u
Number of wooden bricks that Xuan used for each car = 1 u + 9

Number of wooden bricks that Henry had
= 4 x 1 u
= 4 u

Number of wooden bricks that Xuan had
= 10 x (1 u + 9)
= 10 u + 90

Xuan had four times the number of wooden bricks as Henry.

4 x 4 u = 10 u + 90
16 u = 10 u + 90
16 u - 10 u = 90
6 u = 90

1 u = 90 ÷ 6 = 15

Number of bricks that Henry had
= 4 u
= 4 x 15
= 60

Answer(s): 60