45 Mary's money was equal to
25 of Irene's money at first. After Mary spent $2.30 and Irene spent $0.90, Mary had
25 as much money as Irene.
- How much did Irene have at first? Express your answer in 2 decimal places.
- How much did Mary have in the end? Express your answer in 2 decimal places.
| |
Make p the same
(3)x5 |
Mary
(1) |
Irene
(2) |
Make p the same
(4)x2 |
| Before |
25 u |
5 u |
10 u |
20 u |
| Change |
- 11.5 |
- 2.3 |
- 0.9 |
- 1.8 |
| After |
10 p |
2 p |
5p |
10 p |
45 Mary's money =
25 Irene's money
45 Mary's money =
410 Irene's money
Mary's money : Irene's money = 5 : 10
(3) = (4)
25 u - 11.5 = 20 u - 1.8
25 u - 20 u = 11.5 - 1.8
5 u = 9.7
1 u = 1.94
Amount Irene has at first
= 10 u
= 10 x 1.94
= 19.4 (a)
Amount Mary has in the end
= 5 u - 2.3
= (5 x 1.94) - 2.3
= 7.4 (b)
Answers: (a) $19.40; (b) $7.40
