Question

A car starts at 10 a.m. with a speed 50km/hr. At 12a.m. an another can starts with a speed of 70km/hr in same direction on same path. At time the second car will catch the first car ?​

Answer 1

Let car starting at 10am be 'A'

And one starting at 12pm be 'B'

Speed of A = 50km/hr

So.. Distance travelled during 2hrs

= 50 x 2 = 100 km

Now,

The speed of B = 70km/hr

Therefore ..

Relative Speed of B w.r.t to A = 70-50

= 20 km/hr

So time taken to travel 100 km

= 100/20 = 5 hr

So the time at which it will catch car A

= 12+5 pm

= 5pm

... Hope It Helps You ^_^ ...

Answer 2

Explanation:

Distance covered by 1st Car :-

$d = s \times t$

$50 \times 2$

(i) Distance covered = 100 km

Time taken by second car:-

$t = \frac{d}{s}$

From (i) equation, we get distance = 100 km

$\frac{100}{70} = \frac{10}{7}$

(ii) Time taken by the second car = 10÷7 hours