In a jar, the ratio of the number of red balls to the number of pink balls was 1 : 3. Each time, 3 red and 7 pink balls were taken out of the jar. A while later, only 118 pink balls were left in the jar. What was the total number of balls in the jar at first?
| |
Red balls |
Pink balls |
| Before |
1x3 =
3 u |
3x3 =
9 u |
| Change |
- 3 u |
- 7 u |
| After |
0 |
118 |
Since there is no red balls 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 balls at first and taken out the same. LCM of 1 and 3 is 3.
Number of pink balls in the end
= 9 u - 7 u
= 2 u
2 u = 118
1 u = 118 ÷ 2 = 59
Total number of balls in the jar at first
= 3 u + 9 u
= 12 u
= 12 x 59
= 708
Answer: 708
