Justin and Luis had some allowance in the ratio of 5 : 11. They shared some money to buy a necklace for their best friend. The ratio of the amount paid by Justin to the amount paid by Luis was 1 : 2. If Luis was left with $168 and Justin had spent
25 of his money, how much was the necklace they bought?
| |
Justin |
Luis |
| Before |
5 u |
11 u |
| Change |
- 2 u |
- 4 u |
Comparing the
amounts spent |
- 1x2 |
- 2x2 |
| After |
3 u |
168 |
The amount that Justin spent is repeated. Make the amount that Justin spent the same. LCM of 1 and 2 is 2.
Amount that Justin spent
=
25 x 5 u
= 2 u
Amount that Luis spent
= 2 x 2 u
= 4 u
Amount that Luis had left
= 11 u - 4 u
= 7 u
7 u = 168
1 u = 168 ÷ 7 = 24
Price of the necklace
= 2 u + 4 u
= 6 u
= 6 x 24
= $144
Answer(s): $144
