Three girls gave an equal amount of money to buy a present for Lee. Risa used
15 of her money. Betty used
34 of her money and Mary used
23 of hers. They had a total of $235 at first. How much was the present?
|
Risa |
Betty |
Mary |
Total |
Before |
5x6 = 30 u |
4x2 = 8 u |
3x3 = 9 u |
47 u ($235) |
Change |
- 1x6 = - 6 u |
- 3x2 = - 6 u |
- 2x3 = - 6 u |
- 18 u |
After |
4x6 = 24 u |
1x2 = 2 u |
1x3 = 3 u |
29 u |
The three girls gave equal amount of money to buy the present. Make the amount that each spent the same. LCM of 1, 3 and 2 is 6.
Total amount that three girls had at first
= 30 u + 8 u + 9 u
= 47 u
47 u = 235
1 u = 235 ÷ 47 = 5
Cost of the present
= 3 x 6 u
= 18 u
= 18 x 5
= $90
Answer(s): $90