M4maths Previous Puzzles

27 Jan 2021 Speed

The speed of a van increases by 5kmph after every one hour. If the distance travelled in the first one hour was 55 km, what was the total distance travelled in 8 hours?

OPtion

1) 580km
2) 116km
3) 147km
4) 240km
5) 440km
6) 179km
7) 540km
8) 480km
9) 430km
10) None of the above

Solution

Distance travelled in 1ST hour =55 km
Speed of the van increases by 5 kmph
after every one hour. Hence, distance travelled in 2nd hour =60 km
distance travelled in 3rd hour =65 km
and so on Total distance travelled =(55+60+……..+(8 terms))
=8/2(2*55+(8-1)5) =4(110+35) =580km

Correct Option: 1 Best Solution (2)

Billal Hossain   4 years AGO

Total Distance = (n/2)*[2a + (n - 1)*d]
= (8/2)*[2*55 + (8 - 1)*5]
= 4 * [110 + 35]
= 4*145
=580km
So, My option is(1)

Like? Yes (1) | No   

G.S.Kantharao   4 years AGO

55+60+...90=580
My option is 1👈

Like? Yes | No