Betty and Olivium went shopping. After Betty spent $60
m, Olivium had 3 times as much as Betty. If Betty had $21
m more than Olivium at first,
- Express the amount of money that Betty had at first in terms of m.
- If m = 15, find the amount of money that the two lady had left after shopping.
|
Betty |
Olivium |
Before |
1 u + $60m |
3 u |
Change |
- $60m |
|
After |
1 u |
3 u |
(a)
1 u + 60
m = 3 u + 21
m3 u - 1 u = 60
m - 21
m2 u = 60
m - 21
m = 39
m1 u = 39
m ÷ 2 = 19.5
m Betty's amount at first
= 1 u + 60
m = 19.5
m + 60
m = $79.5
m (b)
1 u + 3 u = 4 u
4 u = 4 x 19.5
m = 78
m Amount the two lady had left
= 78 x 15
= $1170
Answer(s): (a) $79.5
m; (b) $1170