Question

Two cars, A and B start from a point P. A starts 20 minutes before B. A moves
at 42 kmph and B moves at 44 kmph. At what distance will car B overtake car
A?​

Answer 1

Answer:

308 km

Step-by-step explanation:

let X be the distance at car B overtake car A.

to cross each other, time required for both car will be same at the point of X distance.

time required for B ( tb) = Distance/speed = X/44

but Car A starts 20 min. before B so distance to be travelled for A = [ X - (20/60)*42 ]

thus time required for A (ta) =

Distance/speed = 1/42* [ X - (20/60)*42 ]

by equating, tb = ta

X/44 = 1/42* [ X - (20/60)*42 ]

we get,. X = 308 km

Answer 2

Car B  will overtake car A at  the distance 308 km.

Step-by-step explanation:

Given :

A and B two cars start from a point P.

20 minutes before B, A starts.

At 42 kmph A car moves.

At 44 kmph B car moves.

To Find :

The distance  at car B overtake car A.

Speed = Distance traveled/ Time taken to travel distance

Solution:

Let  after P  hrs  of Car B travel  Car B catches or overtake Car A.

As given- At 44 kmph B car moves.

 Car B  traveled distance = 44P km

As given-20 minutes before B, A starts.

20 Minutes  $=\frac{20}{60} =\frac{1}{3} hrs.$

Car A Moves for $(P+13)$  hrs

As given- At 42 kmph A car moves.

Car A  traveled distance $=42(P+\frac{1}{3} )$

                                            $=42P+ 14$  km      

Condition for  Car B catches or overtake Car A.

 The distance traveled by Car B = The distance traveled by Car A

$44P=42P+14$

$2P=14$

$P=7$

The distance traveled by Car B $=44P$ km

                                                    $= 44\times 7$ km  $=308$ km.

Thus, Car B  will overtake car A at  the distance 308 km.