Jessie finds coupons

Question

Jessie found a coupon that offers a discount on developing 5 X 7 photos. The first 5 X 7 photo is sold at a regular price of 2.99 additional 5 X 7 photos are 50% off ($1.49) for each 5 X 7 photo

State an equation that represents the cost C, where P, photos are developed

Answer 1

When creating an equation, a good place to start is to think about what the dependent variable is and what the independent variable is. All this means is which variable depends on the other (dependent variable) and which variable is changed due to the other (independent variable). So, in this problem, think to yourself, does the number of photos (P) depend on their cost (C), or does the cost (C) depend on the number of photos (P)? The latter is correct, the cost depends on the number of photos, meaning C is the dependent variable and P is the independent variable.

In a typical equation, y = mx + b, "y" is the dependent variable, "m" is the slope number, "x" is the independent variable, and "b" is a constant (or unchangeable) number. Since we know that C is our dependent variable and P is our independent variable, we can put those in place of "y" and "x" to get: C = mP + b.

Now, we have to find the numbers that go in place of "m" and "b." The slope, "m," is typically noticed when you see words like "per" or "per each" or "for each." So, in this case, the slope number would be 1.49 since it costs $1.49 for each photo. The constant, "b" is a number that is set in stone, or that must be accounted for. In this problem, "b" would be 2.99 because Jessie must pay a set amount of $2.99 for the first photo. So, our equation should now be C = 1.49P + 2.99 when we put 1.49 in place of "m" and 2.99 in place of "b."

We must consider, however, that when you plug in 1 for P, you should get $2.99 since the cost of 1 photo is $2.99. However, our equation does not give us that so we must make the adjustment that "P" should be "P-1" because then, if we plug in 1 for P, we get $2.99 for one photo, which is the correct amount.

Therefore, the equation should be C = 1.49(P - 1) + 2.99.

Answer 2

To get to the right answer you must ask the right questions.

What is the problem asking for? R/ Its asking for an equation that represents the total cost C. That means variable C will represent the cost, and it tells us that variable P will represent the number of photos developed. The problem gives us additional information. The regular price FOR THE FIRST PHOTO is $2.99 , THE REST of photos will cost 50% of the regular price, that means half the price , $1.49.

the first photo will be $ 2.99

C= COST OF FIRST PHOTO+ COST OF THE REST OF PHOTOS AT HALF PRICE.

C=2.99 + COST OF THE REST OF PHOTOS AT HALF PRICE.

The REST of photos will be represented by ( P-1), where 1 represents the first photo,

and (p-1) is the total of photos minus the first photo. The rest of photos (P-1) needs

to be MULTIPLY by HALF the regular price. This multiplication will give us the price

for the rest of photos at half price.

C=2.99 + COST OF THE REST OF PHOTOS AT HALF PRICE.

C= 2.99+(P-1)(1.49) , This formula will work when P > 0

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