Home > Prealgebra > Rates

Eight pens cost $9.20. What is the unit price?

Answer 1

Genesis Amaya

Unit price of pen is #$1.15#

As #8# pens cost #$9.20#

Unit price of pen is #$9.20/8=$1.15#

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Mila Anderson

In support of Shwetank

The unit price (price of 1) is $1.15

Shwetanks method is the one every one uses ( including me ) once they have got used to this type of question and understand what is going on.

#color(blue)("Demonstrating where the shortcut method comes from")#

Using ratio method

We have 8 pens at a total cost of $9.20

Objective: To find the price of one pen (unit price)

As a ratio we have:#" "("cost")/("count of pens") -> ($9.20)/8#

But we need to change the 8 into 1. We can do this by adopting #8-:8#. However, to maintain proportionality what we do to the bottom of the ratio (for multiply or divide) we also do to the top. So we have:

#" "("cost")/("count of pens") -> ($9.20)/8-=($9.20-:8)/(8-:8) = ($1.15)/1# #" "color(magenta)(uarr)# #color(magenta)(" This is where the shortcut comes from.")#

So the unit price (price of 1) is $1.15

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 3

Cameron Arnold

The unit price of one pen is $1.15.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 4

Julian Avila

To find the unit price, divide the total cost by the number of units. In this case, divide $9.20 by 8 pens.

$9.20 / 8 pens =$ 1.15 per pen.

So, the unit price of each pen is $1.15.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.