Atheme park charges different prices for children under age 12, children over age 12, and adults. a family with 2 kids under age 12, 3 kids over age 12, and 3 adults pays $174 for entrance to the park. a mother and father bring their 4 kids under age 12 at a cost of $122. a grandmother who brings her teenage granddaughter to the park pays $46. how much does it cost for an adult to enter the theme park? a. $16 b. $18 c. $20 d. $21 e. $25

Step 1: Assign variable for the unknown that we need to find.

Let x be the charge/person who are under age 12

Let y be the charge/person who are over age 12, and

Let z be the charge/person who are adults.

Step 2: Based on the information given write mathematical equation

Statement 1: "A family with 2 kids under age 12, 3 kids over age 12, and 3 adults pays $174 for entrance to the park"

For Under Age 12, 1 kid charge $x, so 2 kids under age 12 charge will be $2x.

For Over Age 12, 1 kid charge $y, so 3 Kids over age 12 charge will be $3y.

For Adults, 1 Adult charge $z, so 3 Adults charge will be $3z

Based on the above statement which mentions the number of person in the family and total cost of $174, we can write our 1st equation as

2x + 3y + 3z = 174 ⇒ 1st Equation

Statement 2: "A mother and father bring their 4 kids under age 12 at a cost of $122"

4 kids under 12 will be charged $4x, & 2 Adults (Mother and father) will be charged $2z, and total cost is given as $122.

Based on the above statement 2, we can write the 2nd equation as

4x + 2z = 122 ⇒ 2nd Equation

Statement 3: A grandmother who brings her teenage granddaughter to the park pays $46.

Grandmother will be considered an adult with teenage granddaughter who need to be considered as kid over age 12.

So we can write the third equation as

y + z = 46 ⇒ 3rd equation.

Step 3: Solve the three equation using substitution method

2x + 3y + 3z = 174 ⇒ 1st Equation

4x + 2z = 122 ⇒ 2nd Equation

y + z = 46 ⇒ 3rd equation

Factoring 3 in the left side of the last two terms of 1st equation we get...

2x + 3(y + z) = 174

Then substituting 46 for y + z we get

2x + 3(46) = 174

2x + 138 = 174 { Subtracting 138 on both sides }

2x +138 - 138 = 174 - 138 {Combining like terms on either side of the equation}

2x = 36 {Dividing 2 on both sides}

2x/2 = 36/2 {Simplifying each fraction}

x = 18

Substituting 18 for x in 2nd equation, 4x + 2z = 122

4(18) + 2z = 122

72 + 2z = 122 {Subtracting 72 on both sides of the equation}

72 + 2z - 72 = 122 - 72 {Combining like terms on both sides of the equation}

2z = 50 {Dividing by 2 on both sides}

2z/2 = 50/2 {Simplifying fraction on both sides of equation}

z = 25

Substituting 25 for z in the 3rd equation y + z = 46

y + 25 = 46 { Subtracting 25 on both sides of the equation }

y + 25 - 25 = 46 - 25 {Combining like terms on either side of the equation}

y = 21

Conclusion:

The cost for an Kid who are under age 12 to enter the theme park = $18

The cost for an Kid who are over age 12 to enter the theme park = $21

The cost for an adult to enter the theme park = $25

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x