Question

The speed of  a Hyundai car increases by 2 km/hrs. after every one hour. If the distance covered in the first hour was 35 km then what was the total distance covered in 12 hours.
1. 550 km
2. 552 km
3. 560 km
4. 570 km

Answer 1

Correct Answer - Option 2 : 552 km

Given

speed of car in 1st hour = 35 km/hr 

Formula Used 

S_n = n/2[2a + (n-1)d]

Calculation:

Series of a speed – 35, 37, 39, 41, 

Sum of A.P. formula

S_n = n/2[2a + (n-1)d]

⇒(12/2)[2 × 35 + (12 – 1)2]  = 6[70+22] = 552 km.

∴ total distance covered by car in 12 hours is 552 km