Question

the time it takes to fly from los angeles to new york varies inversely as the speed of the plane. if the trip takes 6 hours at 900 km/h,how long would it take at 800 km/h

Answer 1

Inverse variation means y=k/x  (direct variation is y=kx) so we can use the info given to find the constant k

y=k/x

6=k/900

k=6(900)

k=5400 so the equation is:

y=5400/x  or more accurately for this problem

t(v)=5400/v  then:

t(800)=5400/800

t(800)=6.75 hours