What is 20 percent of 240???

If x-1 and x+3 are the factors of x3+10x2+ax+b find a and b

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?

Find the unit rate. enter your answer as a mixed number. a fertilizer covers 2/3 square foot in 1/2 hour.