PSLE At first, a container contained 52 pink beads and some black beads. After some pink beads were removed,
37 of the beads were black. After 21 green beads were added to the container and now,
310 of the beads were black. What was the number of pink beads removed?
|
Black beads |
Pink beads |
Green beads |
Total |
Before |
3 u |
52 |
0 |
|
Change 1 |
|
- ? |
|
+ ? |
After 1 |
3 u |
4 u |
0 |
7 u |
Change 2 |
|
|
+ 21 |
+ 3 u |
After 2 |
3 u |
4 u |
3 u |
10 u |
Some pink beads were removed at first. However, when 21 green beads were added, the number of pink beads remains unchanged.
Number of green beads added
= 10 u - 7 u
= 3 u
3 u = 21
1 u = 21 ÷ 3 = 7
Number of pink beads removed
= 52 - 4 u
= 52 - 4 x 7
= 52 - 28
= 24
Answer(s): 24