In a bag, the ratio of the number of grey beads to the number of gold beads was 1 : 3. Each time, 3 grey and 7 gold beads were taken out of the bag. A while later, only 92 gold beads were left in the bag. What was the total number of beads in the bag at first?
|
Grey beads |
Gold beads |
Before |
1x3 = 3 u |
3x3 = 9 u |
Change |
- 3 u |
- 7 u |
After |
0 |
92 |
Since there is no grey beads left, this means that the number of grey marbles at first is the same as the number of grey marbles taken out.
Make the number of grey beads at first and taken out the same. LCM of 1 and 3 is 3.
Number of gold beads in the end
= 9 u - 7 u
= 2 u
2 u = 92
1 u = 92 ÷ 2 = 46
Total number of beads in the bag at first
= 3 u + 9 u
= 12 u
= 12 x 46
= 552
Answer: 552