Question

You are driving home from school steadily at 95 km/h for 180 km. It then begins to rain and you slow to 65 km/h. You arrive home after driving 4.5 h. (a) How far is your hometown from school? (b) What was your average speed?

Answer 1

(a) 349.34

(b) 77.63 km/h

Explanation:

Distance you covered before it rain S = 180 km

Speed v = 95/km

Time taken to cover 180 km =
`(S)/(v)`

=
`(180)/(95)`

= 1.89473 hrs.

Total time to cover the distance between school to home T = 4.5 hrs.

Remaining time t = T - t

= 4.5 - 1.89473

= 2.60527 h.

Velocity after travel 180 km. v' = 65 km/h

Distance traveled in this velocity S' = v'(t)

= 2.60527 × 65

= 169.34 km

(a) distance of hometown from school = 169.34 + 180 = 349.34 km.

(b) Your average speed V =
`(S)/(T)`

=
`(349.34)/(4.5)`

= 77.63 km/h