Billy and Mark had some allowance in the ratio of 3 : 8. They shared some money to buy a necklace for their cousin. The ratio of the amount paid by Billy to the amount paid by Mark was 1 : 3. If Mark was left with $46 and Billy had spent
23 of his money, how much was the necklace they bought?
| |
Billy |
Mark |
| Before |
3 u |
8 u |
| Change |
- 2 u |
- 6 u |
Comparing the
amounts spent |
- 1x2 |
- 3x2 |
| After |
1 u |
46 |
The amount that Billy spent is repeated. Make the amount that Billy spent the same. LCM of 1 and 2 is 2.
Amount that Billy spent
=
23 x 3 u
= 2 u
Amount that Mark spent
= 3 x 2 u
= 6 u
Amount that Mark had left
= 8 u - 6 u
= 2 u
2 u = 46
1 u = 46 ÷ 2 = 23
Price of the necklace
= 2 u + 6 u
= 8 u
= 8 x 23
= $184
Answer(s): $184
