**Correct option (d) 17.2s**

**Explanation:**

Given : u = 0, t = 5 sec, v = 108 km/hr = 30m/s

By eq^{n} of motion

v = u + at

or a = c/t = 30/5 = 6m/s^{2} [u = 0]

S_{1} = 1/2at^{2}

= 1/2 x 6 x 52 = 75

Distance travelled in first 5 sec is 75m.

Distance travelled with uniform speed of 30m/s is S_{2}

395 = S_{1 } + S_{2} + S_{3}

395 = 75 + S_{2} + 45

∴ S_{2} = 395 – 120 = 275 m

Time taken to travel 275 m = 275/30 = 9.2sec

For retarding motion, we have

0^{2} – 30^{2 }= 2(– a) × 45

We get, a = 10 m/s^{2}

Now by, S = ut + 1/2at^{2}

45 = 30t + 1/2(-10)t^{2}

45 = 30t - 5t^{2}

on solving we get, t = 3 sec

Total time taken = 5 + 9.2 + 3

= 17.2 sec.