PSLE At first, a container contained 65 brown beads and some red beads. After some brown beads were removed,
35 of the beads were red. After 100 black beads were added to the container and now,
310 of the beads were red. What was the number of brown beads removed?
|
Red beads |
Brown beads |
Black beads |
Total |
Before |
3 u |
65 |
0 |
|
Change 1 |
|
- ? |
|
+ ? |
After 1 |
3 u |
2 u |
0 |
5 u |
Change 2 |
|
|
+ 100 |
+ 5 u |
After 2 |
3 u |
2 u |
5 u |
10 u |
Some brown beads were removed at first. However, when 100 black beads were added, the number of brown beads remains unchanged.
Number of black beads added
= 10 u - 5 u
= 5 u
5 u = 100
1 u = 100 ÷ 5 = 20
Number of brown beads removed
= 65 - 2 u
= 65 - 2 x 20
= 65 - 40
= 25
Answer(s): 25