Raeann bought some pens. She gave
15 of the pens to her cousin and sold
25 of the remaining pens. After that, she bought another 91 pens and had the same number of pens that she bought at first. How many pens did Raeann buy at first?
| Her cousin |
Remaining pens |
Bought pens |
Total |
1x5 =
5 u |
4x5 =
20 u |
|
5x5 =
25 u |
| |
Sold |
Left |
|
|
| |
2x4 |
3x4 |
|
|
| 5 u |
8 u |
12 u |
91 |
|
The remaining number of pens before Raeann bought another 91 pens is repeated. Make the remaining number of pens the same. LCM of 4 and 5 is 20.
Total number of pens at first = 25 u
Number of pens that Raeann had left and bought after that = 12 u + 91
25 u = 12 u + 91
25 u - 12 u = 91
13 u = 91
1 u = 91 ÷ 13 = 7
Total number of pens at first
= 25 u
= 25 x 7
= 175
Answer(s): 175
