PSLE At first, a container contained 62 white balls and some yellow beads. After some white balls were removed,
57 of the balls were yellow. After 36 blue balls were added to the container and now,
513 of the beads were yellow. What was the number of white balls removed?
|
Yellow balls |
White balls |
Blue balls |
Total |
Before |
5 u |
62 |
0 |
|
Change 1 |
|
- ? |
|
+ ? |
After 1 |
5 u |
2 u |
0 |
7 u |
Change 2 |
|
|
+ 36 |
+ 6 u |
After 2 |
5 u |
2 u |
6 u |
13 u |
Some white balls were removed at first. However, when 36 blue balls were added, the number of white balls remains unchanged.
Number of blue balls added
= 13 u - 7 u
= 6 u
6 u = 36
1 u = 36 ÷ 6 = 6
Number of white balls removed
= 62 - 2 u
= 62 - 2 x 6
= 62 - 12
= 50
Answer(s): 50