Find y when x=21/2, if y varies inversely as x and x=5 when y=3

A. 2.5/3=3/4; 6

B. 2.5/3=3/4; 3

C. 2.5/3=5/3; 6

D. 2.5/3=5/4; 3

y varies inversely as x:

y=C/x

C: Constant

Cross multiplication

yx=C

x=5 when y=3

Replacing in the equation above:

(3) (5) = C

when x=2 1/2=2+0.5→x=2.5, y=?

xy=C

(2.5) (y) = C

Equaling the two equations:

C=C

(2.5) (y) = (3) (5)

2.5/3=5/y

Solving for y. Dividing both sides of the equation by 2.5:

(2.5) (y) / (2.5) = (3) (5) / (2.5)

y=6

Answer:

2.5/3=5/6