1. Estella borrowed $900. Interest on this loan is $108. How much will estella have to repay?

2. You are cooking a 5 1/4 pound roast to serve 14 people. How much meat will each person receive?

$900 + $108 =$1008

5.25/14 =0.3753. How many 4' * 8' sheets of drywall do you need for the walls of a 12' * 20' room, 8ft high?

(12*20*8)/(4*8)=60

4. If ceramic tiles are 8" * 4", how many tiles would it take to cover an area 4' * 6'?

4 feet = 48 inches. 6 feet = 72 inches. (48*72)/(8*4)=1085. If a customer buys 20 2*4's 8ft long, at $4.75 each, how much would the 2*4's cost?

I don't really understand this question. What does "20 2*4's 8ft long" mean?