In a bag, the ratio of the number of red beads to the number of grey beads was 1 : 4. Each time, 3 red and 6 grey beads were taken out of the bag. A while later, only 48 grey beads were left in the bag. What was the total number of beads in the bag at first?
| |
Red beads |
Grey beads |
| Before |
1x3 =
3 u |
4x3 =
12 u |
| Change |
- 3 u |
- 6 u |
| After |
0 |
48 |
Since there is no red beads left, this means that the number of red marbles at first is the same as the number of red marbles taken out.
Make the number of red beads at first and taken out the same. LCM of 1 and 3 is 3.
Number of grey beads in the end
= 12 u - 6 u
= 6 u
6 u = 48
1 u = 48 ÷ 6 = 8
Total number of beads in the bag at first
= 3 u + 12 u
= 15 u
= 15 x 8
= 120
Answer: 120
