PSLE Bobby, Andy and Mark had 75 stickers altogether. Bobby gave
110 of his stickers to Andy and
25 of his stickers to Mark. After that, all three boys had the same number of stickers. What was the difference in the number of stickers between Andy and Mark at first?
|
Bobby |
Andy |
Mark |
Total |
Before |
10 u |
4 u |
1 u |
15 u |
Change 1 |
- 1 u |
+ 1 u |
|
|
Change 2 |
- 4 u |
|
+ 4 u |
|
After |
5 u |
5 u |
5 u |
15 u |
Comparing between Bobby, Andy and Mark in the end |
1x5 = 5 u |
1x5 = 5 u |
1x5 = 5 u |
3x5 = 15 u |
Fraction of stickers that Bobby had left
= 1 -
110 -
25 = 1 -
110 -
410 =
510 Total number of stickers
= 3 x 5 u
= 15 u
15 u = 75
1 u = 75 ÷ 15 = 5
Difference in the number of stickers between Andy and Mark at first
= 4 u - 1 u
= 3 u
= 3 x 5
= 15
Answer(s): 15