Eric, Henry and Caden had 72 erasers. After Eric used 15 erasers and Henry used
12 of her erasers, Eric had thrice as many erasers left as Henry. Caden bought another 24 erasers, he had four times the number of erasers Henry had left. How many erasers did Caden have at first?
| |
Eric |
Henry |
Caden |
Total |
| Before |
3 u + 15 |
2 u |
4 u - 24 |
72 |
| Change |
- 15 |
- 1 u |
+ 24 |
|
| After |
3 u |
1 u |
4 u |
|
Comparing Eric
and Henry in the end |
3 |
1 |
|
|
Comparing Caden
and Henry in the end |
|
1 |
4 |
|
Number of erasers that Eric had in the end
= 3 x 1 u
= 3 u
Number of erasers that Caden had in the end
= 4 x 1 u
= 4 u
Total number of erasers at first
= 3 u + 15 + 2 u + 4 u - 24
= 9 u - 9
9 u - 9 = 72
9 u = 72 + 9
9 u = 81
1 u = 81 ÷ 9 = 9
Number of erasers that Caden had at first
= 4 u - 24
= 4 x 9 - 24
= 36 - 24
= 12
Answer(s): 12
