PSLE Vaidev, David and Fred had 648 stickers altogether. Vaidev gave
320 of his stickers to David and
14 of his stickers to Fred. After that, all three boys had the same number of stickers. What was the difference in the number of stickers between David and Fred at first?
|
Vaidev |
David |
Fred |
Total |
Before |
20 u |
9 u |
7 u |
36 u |
Change 1 |
- 3 u |
+ 3 u |
|
|
Change 2 |
- 5 u |
|
+ 5 u |
|
After |
12 u |
12 u |
12 u |
36 u |
Comparing between Vaidev, David and Fred in the end |
1x12 = 12 u |
1x12 = 12 u |
1x12 = 12 u |
3x12 = 36 u |
Fraction of stickers that Vaidev had left
= 1 -
320 -
14 = 1 -
320 -
520 =
1220 Total number of stickers
= 3 x 12 u
= 36 u
36 u = 648
1 u = 648 ÷ 36 = 18
Difference in the number of stickers between David and Fred at first
= 9 u - 7 u
= 2 u
= 2 x 18
= 36
Answer(s): 36