36 pairs
because 2 spots = 1 pair
so 2x=72
and your answer will be 36 pairs
Find the average value:
40 minutes + 50 minutes = 90 minutes
90 minutes/2 = 45 minutes
Together it will take them 45 minutes to clean the house
125 minutes, or 2 hours and 5 minutes.

cross multiply
5*175=7x
875=7x

125=x
$20 / 8 dessert dishes = $2.50
The cost of each dish is $2.50.