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

	Gwen	Hilda	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 Gwen and Hilda shared the cost of their younger sister's gift equally, the amount each paid for the gift is the same. 

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

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

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

Answer(s): 81.3%