Question

Can some help me. I'm totally stumped with this problem:

y varies inversely with x, and x = 120 when y =90. Find the inverse variation equation and use it to find the value of x when y = 30.
210 40 360 22.5

y varies inversely with x. Find the inverse variation equation if x = 1.4 when y = 70.
I got the first part of the answer xy = 98 y/x = 98
The problem is that I'm not sure how the xy goes.

Thank you

Answer 1

inverse variation is y = k/x
where k is a constant
x = 120 when y = 90
90 = k/120
k = 10800

so relation between y and x is

y = 10800/x

when y = 30
30 = 10800 / x
x = 10800 / 30 = 360