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

	Anna	Xandra	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 Anna and Xandra shared the cost of their mother's gift equally, the amount each paid for the gift is the same. 

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

Amount that Anna spent on the gift
= 16 u - 3 u
= 13 u

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

Answer(s): 81.3%