y varies inversely with x and y = 5 when x = 2.

Which is the inverse variation equation for the relationship?
A.y=2x
B.y=1/2x
C.y=10/x
D.y=x+2

Question

y varies inversely with x and y = 5 when x = 2.

 

Which is the inverse variation equation for the relationship?
A.y=2x
B.y=1/2x
C.y=10/x
D.y=x+2

anonymous · Answer

Last time I annoy you I promise! @ranga

ranga · Answer

"y varies inversely with x"  means:
y = k * 1/x
when x =2, y = 5.  Put the numbers above and solve for k.

anonymous · Answer

5=k*0.2?

ranga · Answer

x is 2  not 0.2

anonymous · Answer

oh sorry. whoops

anonymous · Answer

5=k*2?

anonymous · Answer

in other words y=2x? which would b a?

ranga · Answer

No.  This is inverse variation.  So y = k * 1 / x

anonymous · Answer

Then it might be B.?

ranga · Answer

Put x = 2, y = 5 in y = k * 1 / x
5 = k * 1 / 2  = k/2
multiply both sides by 2
2*5 = k
k = 10
So y = 10 / x

anonymous · Answer

oh ok I get it now thanks again your a lifesaver!!!! :))))

ranga · Answer

you are welcome.