Question 1173031
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The responses from the other tutors use what is probably the algebraic method typically seen in textbooks to find the answer.  Here is an alternative that I find makes finding the answer easier.<br>
Given that 5 years ago Barbra was 4/5 of Bill's age, let their ages 5 years ago be 4x and 5x.<br>
"10 years from now" is 15 years after "5 years ago"; so their ages 10 years from now will be 4x+15 and 5x+15.<br>
The ratio of their ages then will be 7/8:<br>
{{{(4x+15)/(5x+15) = 7/8}}}
{{{8(4x+15) = 7(5x+15)}}}
{{{32x+120 = 35x+105}}}
{{{3x=15}}}
{{{x=5}}}<br>
Their ages 5 years ago were:
Barbra: 4x = 20
Bill: 5x = 25<br>
So their current ages are 25 and 30.<br>
Their ages 10 years from now will be 35 and 40 -- a ratio of 7:8.<br>