A car moves at 80 km/hr in the first half of the total time of —— 40km/hr :

A car moves at 80 km/hr in the first half of the total time of —— 40km/hr in the later half. Its average speed is
(a) 30 km/hr
(b) 40 km/hr
(c) 60 km/hr
(d) 120 km/hr

Anurag Mishra Professor Asked on 18th January 2016 in Maths.
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  • 1 Answer(s)

    Answer: (c) 60 km/hr

    Explanation:-
    Formula-
    Average speed = total distance/total time

    Given-
    Speed (S 1) = 80 t/2  and speed (S 2) = 40 t/2
    Then,  S 1 = 40 t  and  S 2 = 20 t

    Total distance = S 1 + S 2
    = 40 t + 20 t
    = 60 t

    Total time = t/2 + t/2 = t

    So, average speed = 60 t/t
    = 60 km/hr

    Hence, the correct answer is option (c) 60 km/hr.

    Anurag Mishra Professor Answered on 29th January 2016.
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