Question

There are 85 plates of fried noodle for 80 people. Each adult eats 2 plates of fried noodle and every three children share 1 plate of fried noodle. How many adults and
children are there?

Answer 1

Let the no of adults be x and the no of children be y then X+y = 80 and 2x + y/3=85 solve the equations and you will get 35 adult and 45 children

Answer 2

Let us consider there are 'x' adults  
And there fore no.of children =(80-x)
From given question we get no.of plates = (x)*2 + (80-x)/3 =  85
6x+80-x = 85*3 =   255
5x+80 = 255
5x = 255 - 80 = 175
x = 175/5 = 35
Therefore no.of adults = x = 35 
No.of children = 80-x = 80-35 = 45