Question

lamp posts are placed 30 metres apart along the road how long will a car travelling at 45 km an hour take to pass 6 lamp posts not counting the first of them

Answer 1

Since we are working with metres, we convert the speed into m/s

We do this by multiplying the speed in km/h by 5/18

45×5/18=25/2

This gives :12.5m/s

The distance covered excluding the first post we have :5×30=150m

For us to get the time taken we use the formulae : Time=Distance/Speed

150m/12.5m/s=12

The time taken is 12 seconds.

Answer 2

Answer:

0.00333 hrs

Step-by-step explanation:

There are 6 lamp posts

Distance between 2 lamp posts = 30 meters

So, total distance between first and sixth lamp post = $5 \times 30$

                                                                                     = $150$

So, Total distance = 150 m

1 m = 0.001 km

So, 150 m = $0.001  \times 150$

150 m =0.15 km

So, Distance = 0.15 km

Speed = 45 km/hr

$Time = \frac{Distance}{Speed}$

$Time = \frac{0.15}{45}$

$Time =0.00333$

So, it will take 0.00333 hrs to cover the distance