Abi bought some marbles. She gave
15 of the marbles to her cousin and sold
25 of the remaining marbles. After that, she bought another 65 marbles and had the same number of marbles that she bought at first. How many marbles did Abi buy at first?
| Her cousin |
Remaining marbles |
Bought marbles |
Total |
1x5 =
5 u |
4x5 =
20 u |
|
5x5 =
25 u |
| |
Sold |
Left |
|
|
| |
2x4 |
3x4 |
|
|
| 5 u |
8 u |
12 u |
65 |
|
The remaining number of marbles before Abi bought another 65 marbles is repeated. Make the remaining number of marbles the same. LCM of 4 and 5 is 20.
Total number of marbles at first = 25 u
Number of marbles that Abi had left and bought after that = 12 u + 65
25 u = 12 u + 65
25 u - 12 u = 65
13 u = 65
1 u = 65 ÷ 13 = 5
Total number of marbles at first
= 25 u
= 25 x 5
= 125
Answer(s): 125
