Answer:
157.5 hours
Explanation:
If Craig continued to work 21 hours for 7.5 months he would work a total of 157.5 hours.
Why?
Because if you multiply 21 seven times you get a total of 147 hours, but we still have the .5 of the month so take 21 and divide it by 2 which gives us 10.5 hours.
When you have both you outcomes ready you add 147 and 10.5 hours
Which gives us 147+10.5=157.5 hours.
Good luck :)