The speed of a car increases by 2 kms after every one hour. If the distance travelling in the first one hour was 35 kms. what was the total distance travelled in 12 hours?

Question: The speed of a car increases by 2 kms after every one hour. If the distance travelling in the first one hour was 35 kms. what was the total distance travelled in 12 hours?

Solution:
Total distance travelled in 12 hours =(35 + 37 + 39 + ..... upto 12^th terms)
This is an arithmatic progression with first term, a = 35, number of terms,
n = 12, d = 2.

Required distance = (12/2)[2 × 35 + {12 - 1) × 2]
= 6(70 + 22)
= 552 kms.