Question

2. A machine burns m gallons of oil each hour on weekends and ngallons each hour on weekdays. How many gallons of oil are burnedin a week?48m + 120n168mn120m + 24n120m + 48n2m + 5n

Answer 1

The question says the machine uses up m gallons of oil each hour on weekends.

This means that if the machine works for 24 hours each day, it implies that:

$\text{Total amount of oil used up in a day = 24}\times m=24m$

There are only two days on weekends i.e. Saturday and Sunday.

This means that if the amount of oil used in 1 day in the weekend is 24m, then we can say:

Saturday: oil used is 24m

Sunday: oil used is 24m

Total oil used during the weekend is:

$24m+24m=48m$