Aptitude - Time and Distance - Discussion

Here in this question, multiple of 4 is the distance traveled. Which is 16.

Very interesting, Thanks, everyone.

By Using alligation method.

4:5=9.
So, 4 * 4 = 16 by walking,
5*9 = 45 by cycle.

Total distance D = 61
4km/hr for 4 hr = 16
9km/hr for 5 hr = 45
Adding 45+16=61.

Hence answer =16.

Hi, its simple,

Total distance = 61 km.
Time taken = 9 hr.

Speed by foot = 4 km/hr.
Speed by bicycle = 9 km/hr.

So split the total hours into 2 parts like 4 hr + 5 hr = 9 hrs.
Multiply it with the speed by foot and bicycle like.

4 hr*4 km/hr = 16 km.
5 hr*9 km/hr = 45 km.

Add 16 + 45 = 61 km (total distance covered).
They asked distance covered by foot. So answer is 16. :).

@All.

Here's my explanation.

Basically, I deduced the given information into two equations:

df = 4tf -----> (1) [ Distance = Speed x Time (Speed mentioned)]
db = 9 x (9 - tb) --->(2) (Same as above)
Where,
df = distance on foot,
tf = time taken on foot,
db = distance on a bicycle,
tb = distance on bicycle

Now, db = 61 - df, as df + db = 61 (given),
Also, tb = 9 - tf, as tf + tb = 9 (given),

So now keeping values together we get,
df = 4tf-->from (1)
61 - df = -5tf + 81 -->from (2)

Solving these two equations, we get the value of tf which comes out to be 4 hours and hence putting this value in (1) we get, df = 16km!

How can 5x=80? just explain it.

Please someone helps me, they have asked only for bare foot then why are we considering the bicycle also?

v = d/t:
we know the time for the full trip (i.e) 9 hours.
He walks bare foot at speed of 4kmph;
why can't we just multiply and find the answer?
d = v * t;
d = 9 * 4.
d = 36km.

Partly means is it not (x/2 )/4+(x/2)/9=9 if d is taken as the total distance?

Please tell me.

This can be solved easily by the rule of alligation.

Take average speed as 61÷9 (speed formula is ditance÷time).

Take the dearer value cheaper value & apply alligation rule.