Three girls gave an equal amount of money to buy a present for Albert. Risa used
16 of her money. Sarah used
25 of her money and Xuan used
45 of hers. They had a total of $117 at first. How much was the present?
|
Risa |
Sarah |
Xuan |
Total |
Before |
6x4 = 24 u |
5x2 = 10 u |
5x1 = 5 u |
39 u ($117) |
Change |
- 1x4 = - 4 u |
- 2x2 = - 4 u |
- 4x1 = - 4 u |
- 12 u |
After |
5x4 = 20 u |
3x2 = 6 u |
1x1 = 1 u |
27 u |
The three girls gave equal amount of money to buy the present. Make the amount that each spent the same. LCM of 1, 2 and 4 is 4.
Total amount that three girls had at first
= 24 u + 10 u + 5 u
= 39 u
39 u = 117
1 u = 117 ÷ 39 = 3
Cost of the present
= 3 x 4 u
= 12 u
= 12 x 3
= $36
Answer(s): $36