# Question 5:

In a flight of 600 km an aircraft was slowed due to bad weather. Its average speed for the trip was reduced by 200km/hr and time of flight increased by 30 minutes. Find the original duration of flight.     [CBSE  2020]

## Solution :

Let the actual speed of flight = ‘x’  km/h

So, time taken by the flight at actual speed hr

Reduse speed of the flight = (x – 200) km/h

So, time taken by the flight at the Reduse speed hr

According to the given condition

⇒  120000×2 = x(x – 200)

⇒  x² – 200 x – 240000 = 0

⇒  x² – 600 x + 400 x – 240000 = 0

⇒  x(x – 600) + 400(x – 600) =0

⇒  (x – 600 )(x + 400) = 0

⇒   x = 600,  – 400(Speed of flight can not be negative)

Hence, speed of flight = 600 km/h

# Question:1

If Ritu were younger by 5 years than what she really is, then the square of her age would have been 11 more than five times her present age. What is her present age ?                   [CBSE Term-2 SQP 2022]

# Question 2:

The sum of areas of two squares is 157 m². If the sum of their perimeters is 68 m, find the sides of the two squares.                     [CBSE 2019]

# Question 3:

If the equation (1 + m²)x² + 2 mcx + c² – a² = 0 has equal roots then show that c² = a²(1 + m²).

[CBSE 2017]

# Question 4:

A train covers a distance of 480 km at a uniform speed. If the speed had been 8 km/h less, it would have taken 3 hours more to cover the same distance. Find the original speed of the train.                [CBSE    2020]