Luke, Lee and Daniel had a total of 35 erasers. The ratio of the number of erasers that Lee had to the number of erasers that Daniel had was 2 : 7. After Luke and Lee each gave away half of their erasers, the 3 children had 28 erasers left. How many erasers did Lee and Daniel have at first?
| |
Luke |
Lee |
Daniel |
Total |
| Before |
2 p |
2 u |
7 u |
35 |
| Change |
- 1 p |
- 1 u |
|
- 7 |
| After |
1 p |
1 u |
7 u |
28 |
Total number of erasers that Luke and Lee gave away
= 35 - 28
= 7
1 p + 1 u = 7 --- (1)
1 p + 1 u + 7 u = 28
1 p + 8 u = 28 --- (2)
(2) - (1)
(1 p + 8 u) - (1 p + 1 u) = 28 - 7
8 u - 1 u = 21
7 u = 21
1 u = 21 ÷ 7 = 3
Total number of erasers that Lee and Daniel had at first
= 2 u + 7 u
= 9 u
= 9 x 3
= 27
Answer(s): 27
