Question 1083024
The distance between joe's house nd the supermarket is X km .
He drive from his house to the supermarket at an average speed of Y km/h .
from the supermarket Joe return to his house, along the same route, at an average speed that is one and a half times faster than the original average speed of Y km/h.
 Calculate the overall average speed at which Joe drove from his house to the supermarket nd back.leave ur answer in terms of Y.
:
let a = average speed for the round trip
write a time equation; time = dist/speed
{{{x/y}}} + {{{x/(1.5y)}}} = {{{(2x)/a}}}
multiply by 3ay, clear the denominators
3ax + 2ax = 3y(2x)
5ax = 6xy
divide both sides by x
5a = 6y
a = {{{6/5}}}y is the average speed for the round trip