Question

to mail a first - class letter, the us postal service charges $0.34 for the first ounce and $0.21 for each additional ounce. it cost $1.18 to mail your letter. how many ounces does your letter weigh?

Explanation:

Step1: Subtract the cost of the first - ounce

Let the weight of the letter be $x$ ounces. The cost of the first ounce is $0.34$ dollars. We first subtract this from the total cost. So the remaining cost for the additional ounces is $1.18 - 0.34=0.84$ dollars.

Step2: Calculate the number of additional ounces

Since each additional ounce costs $0.21$ dollars, the number of additional ounces $n$ is given by the formula $n=\frac{0.84}{0.21}$. So $n = 4$ ounces.

Step3: Calculate the total weight of the letter

The total weight of the letter $x$ is the first ounce plus the additional ounces. So $x=1 + 4=5$ ounces.

Answer:

5