Rachel's and Xuan's savings were in the ratio of 4 : 7. Both of them shared the cost of their older brother's present equally. Rachel's remaining savings was ¹₅ as much as Xuan's savings. What percentage of her savings did Rachel spend? Correct the answer to 1 decimal place.

	Rachel	Xuan	Difference
Before	4x4 = 16 u	7x4 = 28 u	3x4 = 12 u
Change	- 13 u	- 13 u
After	1x3 = 3 u	5x3 = 15 u	4x3 = 12 u

Since Rachel and Xuan shared the cost of their older brother's present equally, the amount each paid for the present is the same. 

So, the difference in the amounts between Rachel and Xuan at first and in the end remains the same.  Make the difference in the amounts between Rachel and Xuan at first and in the end the same. LCM of 3 and 4 is 12.

Amount that Rachel spent on the present
= 16 u - 3 u
= 13 u

Percentage of her savings that Rachel spent
= ¹³₁₆ x 100%
≈ 81.3%

Answer(s): 81.3%