d Problem22: To get to the camp in time, tourists had to go with a speed 4km/h. They went with that speed half of the road, but then they drove with a bus and arrived to the camp 2h 20min before the planned time. How many kilometers did tourists drive with the bus, if the speed of the bus was 60km/h?​ | Job Exam Rare Mathematics (JEMrare) - Solved MCQs

# ​Solution: This problem can be solved using distance formula;

$s=vt$

Here we suppose;

Speed of Tourists=v1=4 km/h

speed of bus=v2=60km/h

Total time to be taken by the tourists to reach the camp without bus=t

Time taken by tourists when bus used=t-2h20min=t-140min

let the total distance is ‘x’ but half is travelled without bus and other half by bus!

for first half distance=s1 =x/2

for second half distance=s2=x/2

Using s=vt formula for first half;

$\frac{x}{2}=4\times t$—1

for second half using same formula;

$\frac{x}{2}=60\times (t-140)$—-2

bothe above equations are showing equal distances so,

$4\times t=60\times (t-140)$

we get after simplification,

$56t=8400$

so,

$t= 150 min$

dividing by 60 to get in hours;

$t=2.5 hours$

put this value of ‘t’ in any of the above equations , say we put in (1)

we get;

$\frac{x}{2}=4 \times2.5$

we get,

$x= 20 km$

So they travelled with the bus 20 kilometers