Question

The speed of a car is 20 km/h for the first three hours and 30 km/h for the next "t" hours. Find the "t" value (in hours) if the total distance traveled by car is 150 km.

• A. 2 hour
• B. 3 hour
• C. 4 hour
• D. 5 hour

Answer 1

The correct option is B 3 hour

Total distance covered by the car = 150 km
As we know,
Distance = speed × time

For the first 3 hours:
Speed = 20 kmph
Distance covered in the first 3 hours = speed of the car x time taken
$\Rightarrow 20\times 3=60$ km

For the next "t" hours :
Speed = 30 kmph
Distance covered in the next "t" hour = speed of the car x time taken
$\Rightarrow 30\times t=30t$ km

Total distance covered by car = Distance covered in the first 3 hours + Distance covered in the next "t" hour


$\Rightarrow 150=60+30t$
$\Rightarrow 150-60=30t$
$\Rightarrow 90=30\times thours\Rightarrow t=\frac{90}{30}\Rightarrow t=3hours$

Hence, the time taken "t" is 3 hours.