Barbara bought some rings and bracelets for her friends. The price of each ring was $3.70 while the price of each bracelet was $13.90. For every 7 bracelets bought, she was given one such ring for free. After receiving the free rings, the number of rings was ¹₃ of the number of bracelets bought. If Barbara paid a total of $920.10, how much more did she pay for the bracelets than the rings?

Bracelets	Rings
3x7	1x7
Bought	Free	Bought
7x3	1x3
21 u	3 u	4 u

	Bracelets	Rings
	Bought	Free	Bought
Number	21 u	3 u	4 u
Value	$13.90	0	$3.70
Total value	291.9 u	0	14.8 u

The number of bracelets bought is the repeated identity. Make the number of bracelets bought the same.  LCM of 3 and 7 is 21.

Cost of the bought bracelets
= 21 u x 13.90
= 291.9 u

Cost of the bought rings
= 4 u x 3.70  
= 14.8 u

Total cost of the bought items
= 291.9 u + 14.8 u
= 306.7 u

306.7 u = 920.10

1 u = 920.10 ÷ 306.70 = 3

Amount that she paid more for the bracelets than the rings
= 291.9 u - 14.8 u 
= 277.1 u
= 277.1 x 3
= $831.30

Answer(s): $831.30