Risa, Yen, Tommy and Mary shared some erasers. Risa and Yen took
13 of the total number of erasers while Tommy and Mary took the rest. Yen had four times as many erasers as Risa and Mary had 72 erasers. Given that Mary had twice as many erasers as Yen, how many erasers were there altogether?
Risa |
Yen |
Tommy |
Mary |
Total |
1x5 |
2x5 |
3x5 |
1 |
4 |
|
|
|
|
1x4 |
|
2x4 |
|
1 u |
4 u |
2 u |
8 u |
15 u |
Number of erasers that Yen had is repeated. Make the number of erasers that Yen had the same. LCM of 4 and 1 is 4.
Number of erasers that Mary had = 8 u
8 u = 72
1 u = 72 ÷ 8 = 9
Total number of erasers
= 15 u
= 15 x 9
= 135
Answer(s): 135