[A]. 14 km
[B]. 15 km
[C]. 16 km
[D]. 17 km
✅ The correct answer is option C.
Let the distance travelled on foot be x km.
Then, distance travelled on bicycle = (61 -x) km.
Let the distance travelled on foot be x km.
Then, distance travelled on bicycle = (61 -x) km.
So,
x
+
(61 -x)
= 9
4
9
9x + 4(61 -x) = 9 x 36
5x = 80
x = 16 km.