The equation for:

Judy and Linda agree to share the cost
of a $21 pizza based on how much each one ate. If Judy ate 3/4 of the amount that Linda ate, how much should each pay?
what is the formula please.

if Linda paid x, then Judy should pay 3/4 x

Add it all together to get the whole cost:

x + 3/4 x = 21
7/4 x = 21
x = 21 * 4/7 = 12

So, Linda paid $12, Judy paid $9

To find out how much each person should pay, we need to use the concept of proportions.

Let's assume that Linda ate x amount of the pizza. Since Judy ate 3/4 of the amount that Linda ate, Judy must have eaten (3/4) * x amount of the pizza.

Now, let's assign variables to the amount each person should pay. Let's say Judy will pay J dollars, and Linda will pay L dollars.

Since the total cost of the pizza is $21, we can say that J + L = $21.

Now, we need to express the proportion of how much each person ate in terms of the money they should pay. The proportion can be expressed as:

Judy's share / Linda's share = J / L = Judy's portion of pizza / Linda's portion of the pizza

Since Judy ate (3/4) * x and Linda ate x, the proportion becomes:

J / L = (3/4) * x / x

Now, simplify the proportion:

J / L = 3/4

Cross-multiplying, we get:

4J = 3L

Now, substitute J + L = $21 into the equation:

4J = 3(21 - J)

Simplify:

4J = 63 - 3J

Combine like terms:

7J = 63

Divide both sides by 7:

J = 9

Now, substitute the value of J back into J + L = $21:

9 + L = 21

Subtract 9 from both sides:

L = 12

Therefore, Judy should pay $9, and Linda should pay $12.

To determine how much each person should pay, we need to set up a proportion based on the amount each person ate. Let's denote the amount Linda ate as "L" and the amount Judy ate as "J".

Given that Judy ate 3/4 of the amount that Linda ate, we can write the equation:

J = (3/4)L

Now, let's assign a variable for the amount each person pays. Let "Jp" be the amount Judy pays and "Lp" be the amount Linda pays.

Since Judy and Linda will share the cost of a $21 pizza, the equation can be written as:

Jp + Lp = $21

To solve this system of equations, we need to substitute J in terms of L into the second equation:

(3/4)L + Lp = $21

Simplifying the equation, we multiply both sides by 4 to eliminate the fraction:

3L + 4Lp = $84

Now we have two equations:

J = (3/4)L
3L + 4Lp = $84

These equations can be used to find the values of Lp and Jp, which represent the amount each person should pay.