PSLE
At first, a container contained 12 yellow marbles and some white beads. After some yellow marbles were added, 47 of the marbles were white. After 48 blue marbles were added to the container and now, 413 of the beads were white. What was the number of yellow marbles added?
|
White marbles |
Yellow marbles |
Blue marbles |
Total |
Before |
4 u |
12 |
0 |
|
Change 1 |
|
+ ? |
|
+ ? |
After 1 |
4 u |
3 u |
0 |
7 u |
Change 2 |
|
|
+ 48 |
+ 6 u |
After 2 |
4 u |
3 u |
6 u |
13 u |
Some yellow marbles were added at first. However, when 48 blue marbles were added, the number of yellow marbles remains unchanged.
Number of blue marbles added
= 13 u - 7 u
= 6 u
6 u = 48
1 u = 48 ÷ 6 = 8
Number of yellow marbles added
= 3 u - 12
= 3 x 8 - 12
= 24 - 12
= 12
Answer(s): 12