The expression 6s^2 can be used to find the surface area of a cube whose side length is s. Find the surface area of a cube whose side length is 4 inches.

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document

How is this equation completed? i cannot find any examples in the book.