Question

If y varies inversely as x and x=12 as y=5, what is the value of y when x=120?

Answer 1

heya.......


"y varies directly as x" means y = kx 

you do not know what k is yet,

 other than that it is some constant number.

 Now plug in the given values, y=12 when x=4,

 in the equation

 5 = 12k

 => k = 2.4

 Now rewrite the equation with the k value you just found 

y = 3k

 Substitute 120 in place of x

 y = 2.4×(120)

 y = 288

tysm....@gozmit

Answer 2

y varies inversely as x
y = k/x
where k is a constant

Now first we find the value of 'k'
for x=12 as y=5
5 = k/12
k = 60

what is the value of y when x=120
y = 60/x
put x = 120
y = 60/120
y = 0.5 ans