Riordan, Harry and Billy bought some croissants. After Riordan ate ⁴₇ of his croissants, Harry ate ³₄ of his croissants and Billy ate 8 croissants, each of them had the same number of croissants left. Riordan had 20 less croissants than Harry at first.

1. How many croissants did Riordan have at first?
2. How many croissants did the 3 of them buy altogether? 

	Riordan	Harry	Billy
Before	7 u	4x3 = 12 u	3 u + 8
Change	- 4 u	- 3x3 = - 9 u	- 8
After	3 u	1x3 = 3 u	3 u

(a)
The number of croissants that Riordan and Harry each had in the end is the same. Make the number of croissants that Riordan and Harry each had in the end the same.  LCM of 3 and 1 is 3.

Number of croissants that Riordan had less than Harry at first
= 12 u - 7 u
= 5 u

5 u = 20

1 u = 20 ÷ 5 = 4

Number of croissants that Riordan had at first
= 7 u
= 7 x 4
= 28 

(b)
Total number of croissants that the 3 of them bought
= 7 u + 12 u + 3 u + 8
= 22 u + 8
= 22 x 4 + 8
= 88 + 8
= 96

Answer(s): (a) 28; (b) 96