You wash dishes for a chemistry laboratory to make extra money to pay for laundry. You earn 6 dollars/hour, and each shift lasts 75 minutes. Your laundry requires 6 quarters/load. How many shifts must you work if you wish to wash 10 loads of laundry.
step 1
we have that
one laundry -----> 6 quarters/load
so
For 10 loads
6(10)=60 quarters
convert to dollars
60(0.25)=$15
step 2
earn 6 dollars/hour -----> 6 dollars/60 minutes------> 1 dollar/10 minutes
each shift lasts 75 minutes
so
In 75 minutes earn
75\10=$7.5
step 3
you have that
he earn $7.5 in each shift
by proportion
7.5/1=15/x
x=15/7.5
x=2 shifts