Mark had 20% more marbles than Ken. Mark gave 30% of his marbles to Ken. Ken in return gave 25% of his marbles to Mark. In the end, Ken had 64 less marbles than Mark. How many marbles did Mark have at first?
| |
Mark |
Ken |
| Before |
120% |
100% |
| Change 1 |
- 36% |
+ 36% |
| After 1 |
84% |
136% |
| Change 2 |
+ 34% |
- 34% |
| After 2 |
118% |
102% |
Number of marbles that Mark had at first in percent
= 100% + 20%
= 120%
Number of marbles that Mark gave to Ken in percent
= 30% x 120%
=
30100 x 120%
= 36%
Number of marbles that Ken gave to Mark in percent
= 25% x 136%
=
25100 x 136%
= 34%
Number of less marbles that Ken had than Mark in the end
= 118% - 102%
= 16%
16% → 64
1% → 64 ÷ 16 = 4
Number of marbles that Mark had at first
= 120%
= 120 x 4
= 480
Answer(s): 480
