Mrs Tan gave Sabrina and Diana some money each on Monday. On Tuesday, Sabrina gave ¹₃ of the amount she had to Diana. On Wednesday, Diana gave ¹₆ of the amount she had to Sabrina. In the end, Sabrina had $27 and Diana had $15. How much did Diana had more than Sabrina at first?

	Sabrina	Diana	Total
Before 1	3 u	?	$42
Change 1	- 1 u	+ 1 u
After 1	2 u	6 p	$42
Before 2	$27 - 1 p	6 p	$42
Change 2	+ 1 p	- 1 p
After 2	$27	5 p ($15)	$42

Amount that Diana had in the end = 5 p

5 p = 15

1 p = 15 ÷ 5 = 3

Working backwards.

Amount that Sabrina had after giving to Diana on Tuesday
= 27 - 1 p
= 27 - 3
= $24

2 u = 24

1 u = 24 ÷ 2 = 12

Amount that Sabrina had at first
= 3 u
= 3 x 12
= $36

Total amount that Sabrina and Diana had 
= 27 + 15
= $42

Amount that Diana had at first
= 42 - 36
= $6

Amount that Sabrina had more than Diana
= 36 - 6 
= $30

Answer(s): $30