There was an equal number of purple and grey beads in a box at first. After 21 grey beads were taken out and 39 purple beads were added into the box, there was
15 as many grey beads as purple beads. Find the number of grey beads in the box at first.
|
Purple beads |
Grey beads |
Before |
5 u - 39 |
1 u + 21 |
Change |
+ 39 |
- 21 |
After |
5 u |
1 u |
The number of purple and grey beads in the box is the same at first.
5 u - 39 = 1 u + 21
5 u - 1 u = 21 + 39
4 u = 60
1 u = 60 ÷ 4 = 15
Number of grey beads at first
= 1 u + 21
= 15 + 21
= 36
Answer(s)36