A farmer 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. The distance travelled on foot is:
14 km
15 km
16 km
17 km
Explanation:
Let the distance travelled on foot be $ x $ km.
Then, distance travelled on bicycle = $\left(61 -x\right)$ km.
| So,$ \dfrac{x}{4} $+$ \dfrac{(61 -x)}{9} $= 9 |
$\Rightarrow$ 9$ x $ + 4$\left(61 -x\right)$ = 9 x 36
$\Rightarrow$ 5$ x $ = 80
$\Rightarrow x $ = 16 km.