Question

Entrance
If a man travels at a speed of 30 km/h, he
reaches his destination 10 min late and if
he travels at a speed of 42 km/h, he
reaches his destination 10min early. The
distance travelled is
(JNV 2019]
(1) 36 km
(2) 35 km
(3) 40 km
(4) 42 km
​

Answer 1

Step-by-step explanation:

Since we have given that

Let the time be 't'.

If speed = 30km/hr

Then it takes 10 minutes late

If speed = 42 km/hr

Then, it takes 10 minutes early.

According to question, it becomes,

\begin{gathered}30(t+10)=42(t-10)\\\\30t+300=42t-420\\\\42t-30t=300+420\\\\12t=720\\\\t=60\end{gathered}

30(t+10)=42(t−10)

30t+300=42t−420

42t−30t=300+420

12t=720

t=60

Answer 2

Answer:

Let the distance be x km.

Then, correct time at a speed of

30 km / h = x/30 - 1060

Correct time at a speed of 42 km /h

= x/42 + 1060

=> x/30 - 1060 = x/42 + 1060

=> x/30 - x/42 = 26

=> x(12)/1260 = 26

=> 72 x = 1260 × 2

=> x = 1260×2/72 => x = 35 km