Question

A plane left 30 min later than its scheduled time to reach its destination 1500 km away. In order to reach in time it increases its speed by 250 km/h. What is its original speed

• A. 1000 km/h
• B. 750 km/h
• C. 600 km/h
• D. 800km/h

Answer 1

The Correct Option is B

Let the original times be \(T\) hours and original speed be \(x\) km/h
\(\frac{1500}{x}=T\)

\(\frac{1500}{x+250}=T-\frac{30}{60}\)

Solving equations (i) and (ii), we get
Speed of plane \(=x=750\) or \(-1000\) (not possible)
\(\therefore\) \(x=750\) km/h
The correct option is (B)