T solve the question, we will make a system of equations
Let there are x children and y adults in that day
Since there are 303 people on that day, then
Add x and y, then equate the sum by 303

Since the admission fee for children is $1.75
Since the admission fee for adults is $6.20
Since the park collected $1220 from admissions, then
Multiply x by 1.75 and y by 6.20, then add the products and equate the sum by 1220

Now, we have a system of equations to solve it
Multiply equation (1) by -6.20 to make the coefficients of y equal in values and different in signs

Add equations (2) and (3) to eliminate y

Divide both sides by -4.45

Substitute x in equation (1) by 148 to find y

Subtract 148 from both sides

There were 148 children and 155 adults