In a pouch, the ratio of the number of green beads to the number of purple beads was 1 : 3. Each time, 3 green and 6 purple beads were taken out of the pouch. A while later, only 72 purple beads were left in the pouch. What was the total number of beads in the pouch at first?
| |
Green beads |
Purple beads |
| Before |
1x3 =
3 u |
3x3 =
9 u |
| Change |
- 3 u |
- 6 u |
| After |
0 |
72 |
Since there is no green beads left, this means that the number of green marbles at first is the same as the number of green marbles taken out.
Make the number of green beads at first and taken out the same. LCM of 1 and 3 is 3.
Number of purple beads in the end
= 9 u - 6 u
= 3 u
3 u = 72
1 u = 72 ÷ 3 = 24
Total number of beads in the pouch at first
= 3 u + 9 u
= 12 u
= 12 x 24
= 288
Answer: 288
