Question 1132886
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Let k be the number of hours Kay takes to do the job alone; then k+5 is the number of hours it takes Lynn alone.  We are given that it takes Jack 2 hours to do the job.<br>
So the fractions the three of them do alone in 1 hour are 1/2, 1/k, and 1/(k+5).<br>
Working together, it takes the three of them 60% as long as it takes Kay alone.  Since it takes them 3/5 as long as Kay working alone, in 1 hour the fraction of the job they get done together is 5/3 as much as Kay alone does in 1 hour.  Then the equation to solve is<br>
{{{1/2 + 1/k + 1/(k+5) = (5/3)(1/k)}}}<br>
Multiply everything by the LCM of the denominators, 6k(k+5):<br>
{{{3k(k+5)+6(k+5)+6k = 10(k+5)}}}
{{{3k^2+15k+6k+30+6k = 10k+50}}}
{{{3k^2+17k-20 = 0}}}
{{{(3k+20)(k-1) = 0}}}<br>
Obviously choose the positive solution, k=1.<br>
ANSWER: It takes Kay 1 hour to deliver all the flyers alone.