Question

If a man travels at a speed of 30 km/hr, he
reaches his destination 10 minutes late and if
he travels at a speed of 42 km/hr, he reaches
his destination 10 minutes early. The distance
travelled is :
(A) 36 km
(B) 35 km
(C)40 km
(D) 42 km
​

Answer 1

answer : option (B) 35 km

Let T is the actual time taken to reach the destination by man.

case 1 : if the speed of man , u = 30 km/h , he reaches his destination 10 min late .

e.g., distance between man and destination point , S = speed of man × time taken

= 30 × (T + 1/6) km [ as you know, 10min = 10/60 hour = 1/6 hour ]

so, S = 30(T + 1/6) ........ (1)

case 2 : if the speed of man, v = 42 km/h , he reaches his destination 10 minutes early.

e.g.,. distance between man and destination point , S = speed of man × Time taken

= 42 × (T - 1/6) km

so, S = 42(T - 1/6) ........(2)

from equations (1) and (2),

30(T + 1/6) = 42(T - 1/6)

or, 10T + 10/6 = 14T - 14/6

or, 10/6 + 14/6 = 14T - 10T

or, 24/6 = 4T

or, T = 1 hour

putting T = 1 in equation (1),

S = 30(1 + 1/6) = 30 × 7/6 = 35 km

hence, The distance travelled is 35 km

Answer 2

Answer:

35 km

Step-by-step explanation:

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