Find the greatest common factor:
20x6y + 40x4y2 – 10x5y5
a. 5x4y
b. 10x4y
c. 5x2y5
d. 20x6y

Find the solution of system of equation y= x-4 y=4x+2

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

Ametal rod is 2/5 meters long. it will be cut into pieces that are each 1/30 meters long. how many pieces will be made from the rod?