Correct Answer - Option 4 : 420 km
Given:
The speed of a car increases by 5 km after every one hour. If the distance traveled in the first one hour was 45 km
Formula used:
Sum = n/2(2a + (n - 1)d)
a = first term, d = common difference, number of term
Calculation:
According to the question,
Total distance traveled in 7 hours
⇒ 45, 50, 55, .......Up to 7th term
This is an A.P
First term a = 45, Number of term = 7, and common difference d = 5
Total distance = n/2(2a + (n - 1)d)
⇒ 7/2(2 × 45 + (7 - 1)5)
⇒ 7 × (90 + 30)/2
⇒ 7 × 60
⇒ 420 km
∴ The total distance traveled in 7 hrs is 420 km.
