Question

a car, travelling at a uniform speed of 60 km per hour completes the journey from Chandigarh to lucknow in 4 1/2 hours. If the driver want to complete the journey in 4 hours, at what uniform speed should he drive the car? ANSWER=700

Answer 1

$\large\bf\underline{Given:-}$

• Speed = 60km/hr , Time = 4 ½ hours

$\large\bf\underline {To \: find:-}$

• Speed of car to complete the journey in 4 hours.

$\huge\bf\underline{Solution:-}$

case (1) :-

Car is travelling at a uniform speed of 60km/hr and completed the journey in 4½ hours.

Now

we will calculate the distance covered by car.

• Speed = 60km/hr
• time = 9/2 hours
• Distance = ?

We know that,

≫ Distance = speed × time

so,

Distance = 60km/hr × 9/2hours

Distance = 30 × 9

Distance = 270 km

So

Distance covered by car = 270km.

Case (2) :-

If the car driver wants to complete the journey in 4 hours then,

• Time = 4 hours
• Distance = 270km
• Speed = ?

≫ Speed = Distance/Time

Speed = 270/4

Speed = 67.5km/hr

So,

If the driver want to complete the journey in 4 hours, he drive the car with the uniform speed of 67.5km/hr.

$\rule{200}3$

Answer 2

Given that ,

Speed = 60 km/hr

Time = $\sf 4 \frac{1}{2}$ hr or 9/2 hr

We know that ,

$\large \sf\fbox{Distance = Speed × Time }$

Thus ,

$\sf \mapsto Distance = 60 × \frac{9}{2} \\ \\ \sf \mapsto</p><p>Distance = 30 × 9 \\ \\ \sf \mapsto</p><p>Distance = 270 \: km$

$\therefore\sf \underline{The \: distance \: from \: chandigarh \: to \: lucknow \: is \: 270 \: km}$

Now , when time = 4 hr , the speed of a car will be

$\sf \mapsto270 = Speed \times 4 \\ \\ \sf \mapsto Speed = \frac{270}{4} \\ \\\sf \mapsto Speed = 67.5 \: \: km/hr$

$\sf \therefore \underline{The \: speed \: of \: car \: will \: be \: 67. 5 \: km/hr \: to \: complete \: the \: journey \: in \: 4 \: hr \: }$