1)

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


A) 552 km

B) 500 km

C) 450 km

D) 555 km

E) 455 km

Answer:

Option A

Explanation:

Total distance travelled in 12 hours = (35 + 37 + 39 + .....upto 12 terms).

This is an A.P. with first term, $a = 35$, number of terms, $n = 12$, common difference, $d = 2$.

Required distance $=\frac{12}{5}\left[2\times 35+(12-1)\times 2\right]$ $=6(70 + 22)$ = 552 km.