Answer: 12 adults , 30 kids
Explanation:
Let x represent the number of adult and y represent the number of kids , then from the first statement ;
x + y = 42 ............................. equation 1
For adults , the admission price is $6, the total cost for x adults will be 6x, Also , the admission price for kids is $3 ,this means that the total cost for y kids is 3y. The group spent $162 in all , this means that
6x + 3y = 162 ................................ equation 2
Solving the system of linear equation by substitution method , from equation 1 , make x the subject of the formula , that is
x = 42 - y ................................... equation 3
substitute x = 42 - y into equation 2 , we have
6(42 - y ) + 3y = 162
252 - 6y +3y = 162
252 - 3y = 162
Add 3y to both sides of the equation , we have
252 = 162 + 3y
subtract 162 from both sides of the equation
252 - 162 = 3y
90 = 3y
divide through by 3
Therefore : y = 30
substitute y = 30 into equation 3 ,that is
x = 42 - y
x = 42 - 30
x = 12
Therefore : there are 12 adults and 30 kids