Question 1106819
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1) by logical reasoning....<br>
The difference in their ages is 68 years.
When Ishaan is 5 times as old as William, their ages can be represented by x and 5x; the difference of those is 4x.
So we want to know when 4x is equal to 68.
4x = 68  -->  x = 17.
Ishaan will be 5 times as old as William when William is 17.
William is 4 now; he will be 17 in 13 years.<br>
Answer: Ishaan will be 5 times as old as William 13 years from now.<br>
2) by algebra...<br>
Let x be the number of years it will be until Ishaan is 5 times as old as William.
Their ages x years from now will be 72+x and 4+x; we want 72+x to be 5 times as much as 4+x:
{{{72+x = 5(4+x)}}}
{{{72+x = 20+5x}}}
{{{52 = 4x}}}
{{{13 = x}}}