Question

Find y when x=6 and z=8 if y varies jointly as x and z and y=60 when x=3 and z=4

A. Y=6×6×10; 360
B. Y=5×6×8; 240
C. Y=5×6×10; 300
D. Y=5×5×8; 200

Answer 1

I think it's B because as y varies jointly as x and z,so if x and z are doubled,the y-value will be multiplied by 4 times.