Question

23. A boy covers a distance of 20 km in 2 1/2 hours, partly on foot at the rate
of 5 km/hour and partly on bicycle at the rate of 10 km/hour. Find the
distance covered on foot.​

Answer 1

Step-by-step explanation:

Boy cover distance in 2 1/2 hours

he covers by foot = 5km/hr

In 1 hour he complete 5km

he covers distance by bicycle = 10km /hr

In 1 hour he complete = 10 km

total he cover distance 20 km

x/5 + (20-x ) /10 = 5/2

x +20 =25

x = 25-20

x = 5

Hence, the distance covered by foot is 5 km

Answer 2

Answer:

5 km

Step-by-step explanation:

total time = 2 1\2 = 5\2

total distance = 20 km

let distance covered by foot ne x km

distance covered by bicycle = 20 - x

Time = Distance\Speed

time he take by foot = x\5

time he take by bicycle = (20-x)\10

now,

x\5 + (20-x)\10 = 5\2

(2x+20-x)\10 = 5\2

(20+x)\10 = 5\2

cross multiplication

40+2x = 50

2x = 50 - 40

x = 10\2

x = 5

distance covered by foot = 5 km