<u>Answer:
</u>
The number of adult is 19 and number of children is 11
<u>Solution:
</u>
Given that there were total 30 passengers.
Let the number of adult be x.
Therefore, number of children = 30-x
It is given that the fare for adult = 50$
The fare for x adults will be 
It is also given that the fare for children is 25$
The fare for (30-x) children = 
Now according to the question, 30 passengers paid $1225
50x + 25(30-x) = 1225
50x + 750 - 25x = 1225
25x = 1225-750
25x = 475

x = 19
Therefore number of adult = 19
Number of children = 30-19 = 11
From the given below equations, 25x + 50x = 30(1225) cannot be used to solve the problem.