Question

The speed of a plane was raised by 60% and then the raised speed was reduced by 50%. The speed measured by radar at this point was 2400km/hr. Find the initial speed

Answer 1

Given,

Speed is raised by 60%

Then reduced by 50%

Current speed = 2400 km/hr

To find,

The initial speed of the plane.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

Let, the initial speed = x km/hr

Speed after increasing = x + (x × 60/100) = x + 3x/5 = 8x/5 km/hr

Speed after decreasing = 8x/5 - (8x/5 × 50/100) = 8x/5 - 4x/5 = 8x-4x/5 = 4x/5 km/hr

According to the data mentioned in the question,

4x/5 = 2400

x = 2400×5/4

x = 3000

Hence, the initial speed is 3000 km/hr.