Answer: The no of child and adult are 355 and 170 respectively
Explanation:
Let the no of tickets for child be x
and the no of tickets for adult be y
Given x+y=525.........[1]
19x+40y=13545.........[2]
Multiplying [1] by 19
19x+19y=9975........[3]
Subtracting [3] from [2]
19x+40y-19x -19y= 13545-9975
21y=3570
Dividing both sides by 21
y=170
Putting value of y in [1]
x+170=525
Subtracting 170 both sides
x+170-170= 525-170
x=355
No of child =355
No of adults =170