Question 604809
if number of housework = x then
working wives speed = x/26 works/hours
husbands speed = x/36 works/minutes = x/(36/60) = x/(3/5) = 5x/3 works/hours


if a wife spent 6.5 hours, then number of works = x/26 * 6.5 = 6.5x/26 = 0.25x
and the husband will spend
{{{(0.25x)/(5x/3)}}}
={{{0.25x*3/(5x)}}}
=0.75x/5x = 0.15 hours = 0.15 * 60 = 9 minutes


or, it can be solved simply with direct proportion: (let husband's time = t)
26 hours/6.5 hours = 36 minutes/t
4 = 36 minutes/t
4t = 36 minutes
t = 36/4 = 9 minutes