Question

If a train travelled 9 km/hr slower, it would take one hour more to travel 410 km. The equation representing this situation is :

• A. $\frac{510}{x-9}-\frac{410}{x}=x-1$
• B. $\frac{410}{x-9}-\frac{410}{x}=1$
• C. $\frac{410}{x-9}-\frac{410}{x}=-1$
• D. $\frac{410}{x}-\frac{410}{x-9}=1$

Answer 1

The correct option is B

$\frac{410}{x-9}-\frac{410}{x}=1$

Let the speed of the train be x km/hr.
Distance travelled = 410 km

Time taken to travel 410 km = $\frac{410}{x}$ hours

When the speed is decreased by 9 km/h, the new speed is (x-9)

Time taken to travel 410 km with the new speed is $\frac{410}{x-9}$ hours

According to the question,
$\frac{410}{x-9}-\frac{410}{x}=1$