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

	Opal	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 Opal and Xandra shared the cost of their older brother's souvenir equally, the amount each paid for the souvenir is the same. 

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

Amount that Opal spent on the souvenir
= 16 u - 3 u
= 13 u

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

Answer(s): 81.3%