Tina used 10 1/2 yards of yarn to make three yarn dolls. She used 3 1/2 yards of yarn for the first doll and 4 1/7 yards for the second doll. How much yarn did Tina use for the third doll?

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

Aswimming pool measures 22ft by 12ft and is 4ft deep. if the pool is being filled at 2.5 cubic ft per minute, how long will it take to fill the pool?