On Friday, Abi, Dana, Sarah and Risa spent a total of $109. On Saturday, Abi spent twice of what she spent on Friday, Dana spent the same as what she spent on Friday, Sarah spent $17 less than what she spent on Friday, and Risa spent $8 more than what she spent on Friday. All of them spent an equal amount on Saturday. How much did Abi and Risa spend altogether on Friday?
| |
Abi |
Dana |
Sarah |
Risa |
Total |
| Before |
1 u |
3 u |
3 u + $17 |
3 u - $8 |
$109 |
| Change |
x 3 |
|
- $17 |
+ $8 |
|
| After |
3 u |
3 u |
3 u |
3 u |
|
Total amount that the four girls spent on Friday
= 1 u + 3 u + 3 u + 17 + 3 u - 8
= 10 u + 17 - 8
= 10 u + 9
10 u + 9 = 109
10 u = 109 - 9
10 u = 100
1 u = 100 ÷ 10 = 10
Total amount that Abi and Risa spent on Friday
= 1 u + 3 u - 8
= 4 u - 8
= 4 x 10 - 8
= 40 - 8
= $32
Answer(s): $32
