math
posted by thomas .
On the average 800 pounds of valuable oxides are obtained from every 2 tons of ore mined.What is the ratio of valuable oxides to other material in 100 tons of ore ?
a. 1:400
b. 1:5
c. 1:4
d. 2:1
e. 4:1
please answer and explain

800/2 = x/100