A cyclist moved at a speed of Xkm/h for 2 hours. He then increased his speed by 2 km/h for the next 3 hours.
If the total distance covered is 36 km, calculate his initials speed.
- 12km/h
- 3km/h
- 4km/h
-
6km/h
The correct answer is: D
Explanation
Speed = \(\frac{\text{Distance}}{\text{Time}}\)
From the first statement, speed = xkm/h, t = 2hrs
Therefore, distance = 2xkm
From the second statement, speed = x + 2 ( since speed increased by 2km/h) and t = 3hrs
distance = 3 X (x + 2) = 3x + 6
But total distance = 36km(given)
Total distance = 2x + 3x + 6 = 36 i.e. (dist. from the first statement + dist. from the second statement)
5x + 6 = 36
5x = 36 - 6 = 30
x = (initial speed) = \(\frac{30}{5}\) = 6Km/h
check = total distance = 36 = 2x + 3x + 6 = 12 + 18 + 6 = 36.