There was an equal number of grey and white marbles in a bag at first. After 17 white marbles were taken out and 39 grey marbles were added into the bag, there was
13 as many white marbles as grey marbles. Find the number of white marbles in the bag at first.
| |
Grey marbles |
White marbles |
| Before |
3 u - 39 |
1 u + 17 |
| Change |
+ 39 |
- 17 |
| After |
3 u |
1 u |
The number of grey and white marbles in the bag is the same at first.
3 u - 39 = 1 u + 17
3 u - 1 u = 17 + 39
2 u = 56
1 u = 56 ÷ 2 = 28
Number of white marbles at first
= 1 u + 17
= 28 + 17
= 45
Answer(s)45
