Question

A car is moving at a uniform speed. If the distance travelled(km) and time taken(hr) are in the ratio 4:7, then the time taken to cover 40,000 m is .

• A. 70000 hours
• B. 7000 hours
• C. 700 hours
• D. 70 hours

Answer 1

The correct option is D 70 hours

Distance ∝ Time (Speed is constant)

We know that, if two quantities are directly proportional, then the ratio between the two quantities is constant.

Distance(km) : Time(hr) = 4:7

We know, 1000 m = 1 km
Therefore, 40,000 m = 40 km

$\frac{4}{7}=\frac{40}{x}$

$x=40\times \frac{7}{4}$

$x=70hours$

Therefore, the time taken to cover 40,000 m is 70 hours.