Two people of different heights are walking in two different circles

Let, n1 = # of rounds by person of short height = 100 (given) ; n2 = # of rounds by person of long height ; d1 = distance btw two adjacent steps of short-height person ; d2 = distance bwt two adjacent steps of long-height person.

Using formula, Total distance (D)= (# of rounds) * (# of steps) * (distance bwt two adjacent steps)

According to 2nd given condition, put it in above equation
=> n2*5*d2 = 100*4 *d1
=> n2*d2 = 80*d1 --------(1)

We can observe that # of steps are inversely proportional to distance between two adjacent steps.
=> d1/d2 = (# of steps of long-height person) / (# steps of short-height person) = 3/5 -------(2)

Put eq (2) in eq (1)
=> n2 = (80*3)/5 =48

Let taller person be T and shorter person be S;
Now,
5 steps of T = 4 steps of S
1 step of T = \(\frac{4}{5}\) steps of S
Also,

As,
1 step of T = \(\frac{4}{5}\) steps of S
3 step of T = \(\frac{4*3}{5}\) steps of S --- (1)
AND we also know,3 step of T = 5 step of S

Now we know,

Hence, 5 step of S = 100
So, S = 20 --- (2)
Using (1) and (2)
\(\frac{4*3*20}{5}\)
=48

Hence B