Question

An aeroplane flies 300km in 5 hours. How much distance will be covered if it travels for 7 hours.

Answer 1

Hint: We will use a unitary method to find the distance covered by aeroplane in 7 hours. We will first find the distance travelled by aeroplane in 1 hour and then multiply the distance covered in 1 hour with the given time, that is, 7 hours.

Complete step-by-step solution -
It is given in the question that an aeroplane flies 300 km in 5 hours, then we have to find the distance covered by aeroplane in 7 hours. We will use a unitary method to find the distance covered by aeroplane in 7 hours.
Basically, the unitary method is a mathematical approach in which we will find the value of a single unit and then multiply the value of a single unit with required value. We have given that aeroplane covers 300 kms in 5 hours. We know that $speed=\dfrac{\text{distance}}{time}$ = $\dfrac{300km}{5hrs}$ = $60km/hr$, thus aeroplane will cover 60 km in 1 hour. Now, aeroplane will cover a distance in 7 hours = $7\times 60kms$ = $420kms$.
Therefore, aeroplane will cover 420km in 7 hours.

Note: This is a very basic question of unitary method. Usually if students do not know the unitary method, they may skip such questions in exams. But, now we know what is unitary method, how to implement unitary method in such questions. Also, students may do wrong calculations in hurry because the question is quite basic thus it is recommended to solve the question with patience and not in hurry.