There was an equal number of black and yellow marbles in a packet at first. After 26 yellow marbles were taken out and 42 black marbles were added into the packet, there was
13 as many yellow marbles as black marbles. Find the number of yellow marbles in the packet at first.
| |
Black marbles |
Yellow marbles |
| Before |
3 u - 42 |
1 u + 26 |
| Change |
+ 42 |
- 26 |
| After |
3 u |
1 u |
The number of black and yellow marbles in the packet is the same at first.
3 u - 42 = 1 u + 26
3 u - 1 u = 26 + 42
2 u = 68
1 u = 68 ÷ 2 = 34
Number of yellow marbles at first
= 1 u + 26
= 34 + 26
= 60
Answer(s)60
