Answer
Find out the how long does it take to install one sheet of drywall .
To prove
As given
A carpenter can install 8 sheets of drywall in 10 minutes.
8 sheets = 10 mintues
Now
\(Time\ taken\ for\ installing\ one\ sheet\ of\ drywall = \frac{Total\ time\ taken\ to\ install\ sheets}{Total\ sheets}\)
\(Time\ taken\ for\ installing\ one\ sheet\ of\ drywall = \frac{10}{8}\)
Time taken for installing one sheets of drywall = 1.25 mintues.
Now Find out how long will it take the carpenter to install 60 sheets .
To prove
As given
A carpenter can install 8 sheets of drywall in 10 minutes.
8 sheets = 10 mintues
\(1\ sheet\ time = \frac{10}{8}\ mintues\)
Now for 60 sheets.
\(60\ sheet\ time = \frac{10\times 60}{8}\ mintues\)
\(60\ sheet\ time = \frac{600}{8}\ mintues\)
\(60\ sheet\ time = 75\ mintues\)
As 1 hour = 60 mintues
\(1\ mintues = \frac{1}{60}\ hours\)
Now convert 75 mintues into the hours.
\(Time\ taken\ for\ installing\ 60\ sheets = \frac{75}{60} \ hours\)
Time taken for installing 60 sheets = 1.25 hours.
Therefore the option (A) is correct.
Thus 1.25 minutes take to install one sheet of drywall and 1.25 hours take the carpenter to install 60 sheets .
