Mary had $480 less than Cole. Cole spent 0.9 of his money and Mary spent 0.3 of her money. In the end, Cole and Mary had the same amount of money left. Find the amount of money Mary had at first.
| |
Mary |
Cole |
Difference |
| Before |
10 u |
70 u |
60 u |
| Change |
- 1 u |
- 7 u |
|
| After |
7 u |
7 u |
|
0.9 =
910 Fraction of Cole's amount left
= 1 -
910 =
110 0.3 =
310 Fraction of Mary's amount left
= 1 -
310 =
710 The amount that Cole and Mary each had in the end is the same. Make the numerators the same. LCM of 1 and 7 is 7.
110 of Cole's amount =
710 of Mary's amount
770 of Cole's amount =
710 of Mary's amount
Amount that Mary had less than Cole
= 70 u - 10 u
= 60 u
60 u = 480
1 u = 480 ÷ 60 = 8
Amount that Mary had at first
= 10 u
= 10 x 8
= $80
Answer(s): $80
