Question

(a) If y varies directly as x, and y=24 when x=16, find y when x=12.

(b) In a formula, z varies inversely as P. If Z is 200 when P is 4, find z when P is 10.

Answer 1

(a) 18

(b) 80

Explanation:

(a) let y=kx

so, 24=16k

or, k=24/16 or, k=3/2

now, putting x=12

y=kx

or, y=(3/2)×12

or, y=3×12/2

or, y=36/2

or, y=18

(b) let P=k/z

so, 4=k/200

or, k=800

when P = 10

P=k/z

or, 10=800/z

or, z=800/10

or, z=80