Question

A motor car does a journey in 17.5 hours, covering the first half at 30 km/h and the second half at 40 km
h. Find the distance of the journey. ​

Answer 1

Answer:

Let the total distance be 2X.

Total time =17.5 hours

Time taken to cover X km at 30 km/h = X /30

Time taken to cover X km at 40 km/h = X/40

$\frac{x}{30} + \frac{x}{40} = 17.5$

$\frac{40x + 30x}{1200} = 17.5$

$70x = 17.5 \times 1200$

$x = 300km$

Total distance = 2x

distance of journey =300×2=600 km

Answer 2

let's journey=2x

first half=x/30

second half=x/40

total time = x/30+x/40=17.5

LCM=120

(4x+3x)/120=17.5

7x=17.5×120

x=17.5×120/7

x=300km

2x total journey

2×300= 600km