8 pens cost $4 more than 8 pencils. Harry paid $8 for 4 pens and 4 pencils. What was the cost of a pencil?
To find the cost of a pencil, let's break down the information given step by step.
Let's assume the cost of a pen is "P" dollars and the cost of a pencil is "C" dollars.
According to the first statement, 8 pens cost $4 more than 8 pencils. Mathematically, this can be represented as:
8P = 8C + $4
Now, let's move on to the next statement. Harry paid $8 for 4 pens and 4 pencils. We can use this information to create another equation:
4P + 4C = $8
To solve these two equations, we can use a method called substitution. Rearrange the first equation to solve for P:
8P = 8C + $4
P = C + $0.50
Substitute this value of P into the second equation:
4(C + $0.50) + 4C = $8
Simplify and solve for C:
4C + $2 + 4C = $8
8C + $2 = $8
8C = $6
C = $0.75
Therefore, the cost of a pencil is $0.75.