If k=20 N/m and F=100 N, find x.

If x=0.03 m and k=300 N/m, find F.

In this problem F is the force acting on a spring with constant k. The force F creates a deformation, either by stetching or compressing the spring. Let x be this deformation.

The relation aming F, k and x is: F=k×x.

A. k=20N/m, F=100N.

x=F/k=100/20=5m

B. x=0.03m, k=300N/m

Fe=k×x=300×0.03=9N

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form