Answer:
y = 10
Step-by-step explanation:
based on the question if y varries directly as x
mathematically
y ∝ x
also, y varries inversly as z can be mathematically expressed as
y ∝ 1/z
combining the two expressions
y ∝ x ∝ 1/z
i. e
y = kx/z..... where k is the constant of proportionality
make k the subject of formulae
yz = kx
Divide both sides by x
k =yz/x
when y=100 , x = 5 z =10
k = 100 × 10/5
k = 200
to find y when x = 3 and z = 60
from the equation connecting x,y,z
k =yz/x
200 =60y/3
cross multiply
60y = 200 × 3
60y = 600
divide both sides by 60
y = 10
