PSLE
At first, a container contained 12 yellow marbles and some red beads. After some yellow marbles were added, 710 of the marbles were red. After 45 blue marbles were added to the container and now, 713 of the beads were red. What was the number of yellow marbles added?
|
Red marbles |
Yellow marbles |
Blue marbles |
Total |
Before |
7 u |
12 |
0 |
|
Change 1 |
|
+ ? |
|
+ ? |
After 1 |
7 u |
3 u |
0 |
10 u |
Change 2 |
|
|
+ 45 |
+ 3 u |
After 2 |
7 u |
3 u |
3 u |
13 u |
Some yellow marbles were added at first. However, when 45 blue marbles were added, the number of yellow marbles remains unchanged.
Number of blue marbles added
= 13 u - 10 u
= 3 u
3 u = 45
1 u = 45 ÷ 3 = 15
Number of yellow marbles added
= 3 u - 12
= 3 x 15 - 12
= 45 - 12
= 33
Answer(s): 33