Problem: It is given that x varies directly as y and inversely as the square of z, and that x=10 when y=4 and z=14. Then, when y=16 and z=7,x equals:
Answer Choices:
A. 180
B. 160
C. 154
D. 140
E. 120
Solution:
x=Z2Ky10=142K(4)∴ K=410⋅142
∴x=72410.142⋅16=160