Billy had 50% more marbles than Glen. Billy gave 30% of his marbles to Glen. Glen in return gave 20% of his marbles to Billy. In the end, Glen had 216 less marbles than Billy. How many marbles did Billy have at first?
| |
Billy |
Glen |
| Before |
150% |
100% |
| Change 1 |
- 45% |
+ 45% |
| After 1 |
105% |
145% |
| Change 2 |
+ 29% |
- 29% |
| After 2 |
134% |
116% |
Number of marbles that Billy had at first in percent
= 100% + 50%
= 150%
Number of marbles that Billy gave to Glen in percent
= 30% x 150%
=
30100 x 150%
= 45%
Number of marbles that Glen gave to Billy in percent
= 20% x 145%
=
20100 x 145%
= 29%
Number of less marbles that Glen had than Billy in the end
= 134% - 116%
= 18%
18% → 216
1% → 216 ÷ 18 = 12
Number of marbles that Billy had at first
= 150%
= 150 x 12
= 1800
Answer(s): 1800
