Correct Answer - Option 3 : 19.2 hrs

**Given:**

If speed of car = x km/hr, time = T hrs

If speed of car = (x + 8) km/hr, time = (T -2) hrs

If speed of car = (x – 12) km/hr, time = (T + 4) hrs

**Formula used:**

Distance = Time × Speed

**Calculation:**

Distance = xT ----- (1)

Distance = (x + 8)(T – 2) ----- (2)

Distance = (x – 12)(T + 4) ------- (3)

According to question –

From (1) & (2):

⇒ xT = (x + 8)(T – 2)

⇒ xT = xT + 8T – 2x – 16

⇒ 8T – 2x = 16 ----- (4)

From (1) & (3):

⇒ xT = (x – 12)(T + 4)

⇒ xT = xT – 12T + 4x – 48

⇒ -12T + 4x = 48 ---- (5)

Multiplying equation (4) by 2 and adding to equation (5) –

⇒ (16T – 12T) = (32 + 48)

⇒ 4T = 80

⇒ T = 20 hours

Put this value in equation (4) we get,

⇒ 8(20) – 2x = 16

*⇒** 160 – 2x = 16*

*⇒** 2x = 144*

*⇒** x = 72*

*∴** Distance = xT = 72 × 20 = 1440 km*

*⇒** Distance between A and B = 1440 km*

*And (x + 3) = 75 km/hr*

*∴ **Time taken to travel from A to B with speed of 75 km/hr = 1440/75 = 19.2 hrs*