PSLE
Shiyun and Barbara went shopping together with a total amount of $107.40. Shiyun spent 2 times as much as Barbara. The amount Barbara had left was $23 more than what she had spent. She had 2 times as much money left as Shiyun.
(a) How much money did Barbara spend?
(b) How much money did Shiyun have at first?

	Shiyun	Barbara	Total
Before	2.5 u + 11.5	2 u + 23	107.40
Change	- 2 u	- 1 u
After	0.5 u + 11.5	1 u + 23

(a)
Total amount that Shiyun and Barbara had at first
= (2.5 u + 11.5) + (2 u + 23)
= 2.5 u + 2 u + 11.5 + 23
= 4.5 u + 34.5

4.5 u + 34.5 = 107.4
4.5 u = 107.4 - 34.5
4.5 u = 72.9

1 u = 72.9 ÷ 4.5 = 16.2

Amount that Barbara had at first
= 1 u
= $16.20

(b)
Amount that Shiyun had at first
= 2.5 u + 11.5
= (2.5 x 16.2) + 11.5
= 40.5 + 11.5
= $52

Answer(s): (a) $16.20; (b) $52