Nora bought some necklaces and rings for her friends. The price of each necklace was $4.10 while the price of each ring was $11.30. For every 7 rings bought, she was given one such necklace for free. After receiving the free necklaces, the number of necklaces was ¹₃ of the number of rings bought. If Nora paid a total of $2283.30, how much more did she pay for the rings than the necklaces?

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

	Rings	Necklaces
	Bought	Free	Bought
Number	21 u	3 u	4 u
Value	$11.30	0	$4.10
Total value	237.3 u	0	16.4 u

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

Cost of the bought rings
= 21 u x 11.30
= 237.3 u

Cost of the bought necklaces
= 4 u x 4.10  
= 16.4 u

Total cost of the bought items
= 237.3 u + 16.4 u
= 253.7 u

253.7 u = 2283.30

1 u = 2283.30 ÷ 253.70 = 9

Amount that she paid more for the rings than the necklaces
= 237.3 u - 16.4 u 
= 220.9 u
= 220.9 x 9
= $1988.10

Answer(s): $1988.10