The ratio of the first and second class train fares between two stations is 3:1 and that of the numbers of passengers travelling between the two stations by first and second classes is 1:50. If on a particular day, Rs.1,325 are collected from passengers travelling between the two stations, then the amount collected from the second class passengers is
A. Rs. 1250
B. Rs. 1000
C. Rs. 850
D. Rs. 750

Hint: Here we will first find the ratio of the amount collected by first class passengers and the second class passengers then with the help of that ratio we will calculate the amount collected from second class passengers.

Complete step by step answer:
 Ratio of fare of first and second class ticket = 3:1
Ratio of the passengers travelling by first and second classes = 1:50
As we know that amount of fare = (fare of one passenger) $\times$ (Number of passengers)
So, Ratio of total amount of fare collected from passenger = 3 $\times$ 1:1 $\times$ 50= 3:50
Amount collected from second class passengers
\[
=\dfrac{Part\;of\;second\;class\;passenger\;in\;the\;ratio\;of\;total\;amount}{Sum\;of\;the\;ratio\;of\;total\;amount} \times {Total\;amount\;of\;fare}\\
= \dfrac{{50}}{{3 + 50}} \times 1325\\
= \dfrac{50}{53} \times 1325\\
= 50 \times 25\\
= 1250
\]
Thus, amount collected from the second class passengers is Rs.1250

Hence, Option (A) is correct.

Note: In this type of question we need to put special emphasis on the concept that we need to multiply corresponding terms of the ratios. If we need to find the amount collected from first class passengers then we will subtract the amount collected from second class passengers from the total amount.