Answer:
B. 150 children
Step-by-step explanation:
Let, number of children = x and number of adults = y.
Since, total number of people attended the fair are 350.
So, x + y = 350.
Moreover, charges per child is $2 and adult is $3.
As, total sales are given to be $900.
So, 2x + 3y = 900
Thus, we get the system of equations,
2x + 3y = 900
x + y = 350
We will now solve the equations,
x + y = 350 ⇒ y = 350 - x
So, 2x + 3y = 900 ⇒ 2x + 3(350 -x) = 900 ⇒ 2x + 1050 - 3x = 900 ⇒ -x = -150 ⇒ x = 150.
Then, y = 350 - x ⇒ y = 350 - 150 ⇒ y = 200.
Hence, number of children and adults that attended the fair are 150 and 200 respectively.