Question

When you send mail via the post office, you have an 80% chance that it is delivered to the correct location.If 430 letters are delivered on Monday, then what is a reasonable prediction for the number of letters that aredelivered to the incorrect location?letters delivered incorrectly.On Tuesday, it is reported that 500 letters were delivered to the correct location. Based on this information,how many letters were delivered on Tuesday?total letters

Answer 1

For the first question, we just need to find how many letters are delivered incorrectly. Since we know that 80% of the letters are delivered to the correct location, it means the the remaining 20% of the letters are delivered to a wrong location.

With this, we can solve for the number of letters that were delivered to the incorrect location through multiplying the total number of letters by 20% or 0.20.

Let x be the number of letters that were delivered incorrectly

`x=430(0.20)`
`x=86`

There were 86 letters that are delivered to the wrong location on Monday.

For the second part, we need to know the total number of letters delivered given that 80% of it, which is 500 letters, were delivered to the correct location. Since we know that in order to find the percentage of the letters, we need to divide number of delivered letters to the correct location by the total amount of letters.

Let N be the total amount of letters delivered.

`(500)/(N)=0.80`
`N=(500)/(0.80)`
`N=625`

Therefore, there was a total of 625 letters delivered on Tuesday.