A Man travelled a distance of 61 km in 9 hours. He travelled partly on foot at 4 km/hr and partly on bicycle at 9 km/hr. What is the distance travelled on foot?
12 km
14 km
16 km
18 km
Explanation:
Let the time in which he travelled on foot = x hr
Then the time in which he travelled on bicycle = $\left(9 - x\right)$ hr
distance = speed x time
$\Rightarrow 4x$ + 9$\left(9 - x\right)$ = 61
$\Rightarrow 4x$ + 81 - 9$x$ = 61
$\Rightarrow 5x $= 20
$\Rightarrow x$ = 4
$\Rightarrow $ distance travelled on foot = 4$x = 4 \times 4 $= 16km