Question

The school store sells pens for $2.50 each and pencils for $2.00 each. Dee Dee spent $24.00 to buy a total of 11 pens and pencils. How many pens did Dee Dee buy

Answer 1

Dee Dee bought 4 pens.

Explanation:

Let's use a system of equations to solve this problem. Let P represent the number of pens Dee Dee bought, and let C represent the number of pencils she bought. We have two equations based on the cost and the total number of items:

The cost of the pens (P) at $2.50 each, plus the cost of the pencils (C) at $2.00 each, should equal the total cost of $24.00:

2.5P + 2C = 24

The total number of items (pens and pencils) Dee Dee bought should be 11:

P + C = 11

Now, you can use these two equations to solve for P, the number of pens:

Let's solve the second equation for C: C = 11 - P

Now substitute this expression for C in the first equation:

2.5P + 2(11 - P) = 24

Now, distribute the 2 on the left side:

2.5P + 22 - 2P = 24

Combine like terms:

0.5P + 22 = 24

Subtract 22 from both sides:

0.5P = 24 - 22

0.5P = 2

Now, divide by 0.5 to find P:

P = 2 / 0.5

P = 4

Dee Dee bought 4 pens.