Question

A car covers half a distance at a velocity of 80km/h and the other half at 60km/h,what is the average velocity of the car?

Answer 1

figure the time for each. Let d be half the distance.

time1=d/80
time2=d/60

avgvelocity=2d/(time1+time2)

so figure that out, I recommend do the math on time1+time2 first, solve the fraction issue...

Answer 2

68.57Km/Hr
let X = distance; t1 = x/80*2; t2 =60*2; t = x/ V average.

t1 + t2 = t = x / V average

(x / 160) +(x / 130)= x / V average

x(1/160 + 1/120) = x /V average

x( .014583333) x/V average

( .014583333)= 1/ V average

V average = 1/ ( .014583333)

V average = 68.57 Km/Hr