Correct Answer - Option 3 : 240 sec.

**Given:**

Distance covered by car = 400 m

Speed of car = 36 km/hr.

Distance covered by Truck = 8 km

Speed of truck = 40 m/sec.

**Formula used:**

Speed = Distancee/Time

1 km = 1000 m

1 hr. = 3600 sec.

**Calculations:**

Time taken by car

⇒ 36 km/hr = 400 m/T_{1}

⇒ 36 × (5/18) = 400m /T_{1}

⇒ T_{1} = 400/10

⇒ T1 = 40 sec.

Time is taken by truck

⇒ 40 m/sec. = 8 km/T_{2}

⇒ 40 m/sec. = 8000 m/T_{2}

⇒ T_{2} = 8000/40

⇒ T2 = 200 sec.

⇒ Sum of times = T_{1} + T_{2}

⇒ Sum of times = 40 sec. + 200 sec.

⇒ Sum of times = 240 sec.

**∴ The sum of the times is 240 sec.**