During a sale, 12 necklaces and 11 rings cost $2251. If Zara bought 7 necklaces and 15 rings, she would have spent all her money. Each necklace cost $40 more than a ring. Find the amount that Zara had at first.
| |
Case 1 |
Case 2 |
| |
Necklaces |
Rings |
Necklaces |
Rings |
| Number |
12 |
11 |
7 |
15 |
| Value |
1 u + 40 |
1 u |
1 u + 40 |
1 u |
| Total value |
12 u + 480 |
11 u |
7 u + 280 |
15 u |
Cost of 1 ring = 1 u
Cost of 11 rings = 11 u
Cost of 1 necklace = 1 u + 40
Cost of 12 necklaces = 12 x (1 u + 40) = 12 u + 480
Total cost of 11 rings and 12 necklaces
= 11 u + 12 u + 480
= 23 u + 480
23 u + 480 = 2251
23 u = 2251 - 480
23 u = 1771
1 u = 1771 ÷ 23 = 77
Cost of 7 necklaces = 7(1 u + 40) = 7 u + 280
Cost of 15 rings = 15 u
Amount that Zara had at first
= 7 u + 280 + 15 u
= 22 u + 280
= 22 x 77 + 280
= $1974
Answer(s): $1974
