In a jar, the ratio of the number of gold balls to the number of pink balls was 1 : 3. Each time, 3 gold and 6 pink balls were taken out of the jar. A while later, only 69 pink balls were left in the jar. What was the total number of balls in the jar at first?
| |
Gold balls |
Pink balls |
| Before |
1x3 =
3 u |
3x3 =
9 u |
| Change |
- 3 u |
- 6 u |
| After |
0 |
69 |
Since there is no gold balls left, this means that the number of gold marbles at first is the same as the number of gold marbles taken out.
Make the number of gold balls at first and taken out the same. LCM of 1 and 3 is 3.
Number of pink balls in the end
= 9 u - 6 u
= 3 u
3 u = 69
1 u = 69 ÷ 3 = 23
Total number of balls in the jar at first
= 3 u + 9 u
= 12 u
= 12 x 23
= 276
Answer: 276
