Eugene and Frank had a total of 772 stamps. Eugene gave 1/3 of his stamps to Frank. Frank then gave 1/5 of his stamps to Eugene. In the end, each of them had the same number of stamps. How many stamps did Eugene have at first?
If both have the same number at the end then each has (772/2) = 386
Let E be the number that Eugene started with and F what Frank started with
And F = 772 - E (1)
Eugene gives away (1/3) of his
And from Frank he gets (1/5) ( F + (1/3) E ] = (1/5) ( 772 -E + 1/3)E ) (2)
So at the end, what Eugene started with - what he gave away + what he got from Frank = 336
So
E - (1/3)E + (1/5) (772 - E + (1/3)E ] = 336
(2/3)E + 772/5 + (1/5)(-2/3)E = 336
(2/3)E - (2/15)E = 336 - 772/5
[ 8/15] E = 908 / 5
8E = 2724
E = 340.5 ?????
Are your numbers correct ??? (it's also possible that I made an error !!! )
https://web2.0calc.com/questions/question-corrected
here is the question that's edited
CPhill --
I got your answer ??? but a different number.
Number Eugene starts with: E
Number Frank starts with: F
Eugene gave away 1/3 of his stamps to Frank ...
Now Eugene has: (2/3)E
and Frank has: F + (1/3)E
Frank then gave 1/5 of his stamps to Eugene ...
Now Eugene has: (2/3)E + (1/5)( F + (1/3)E )
and Frank has: (4/5)( F + (1/3)E )
They now have the same number of stamps:
(2/3)E + (1/5)( F + (1/3)E ) = (4/5)( F + (1/3)E )
(2/3)E + (1/5)F + (1/15)E = (4/5)F + (4/15)E
multiply by 15: 10E + 3F + E = 12F + 4E
11E + 3F = 12F + 4E
7E = 9F
Since E + F = 772 ---> F = 772 - E
7E = 9(772 - E)
7E = 6948 - 9E
16E = 6948
E = 434.25
Final result: ?????