David's salary to Liam's salary is 4 : 5. The former saves $730 while the latter saves $770. If Liam's spending to David's spending is in the ratio of 7 : 5, what are David's and Liam's salaries respectively?
- David
- Liam
| David's salary |
Liam's salary |
| 4 u |
5 u |
| Savings |
Spending |
Savings |
Spending |
| $730 |
5 p |
$770 |
7 p |
730 + 5 p = 4 u --- (1)
770 + 7 p = 5 u --- (2)
Make p the same.
(1)
x 75110 +
35 p = 28 u
35 p = 28 u - 5110 --- (3)
(2)
x 53850 +
35 p = 25 u
35 p = 25 u - 3850 --- (4)
(3) = (4)
28 u - 5110 = 25 u - 3850
28 u - 25 u = 5110 - 3850
3 u = 1260
1 u = 1260 ÷ 3 = 420
(a)
David's salary
= 4 u
= 4 x 420
= $1680
(b)
Liam's salary
= 5 u
= 5 x 420
= $2100
Answer(s): (a) $1680; (b) $2100
