4.3+Solving+Problems+with+Rates+-+4.4+Buying+Beads+-+2010-2011

 December 6th, 2010

 GG

 7H

__Problem 4.4- Buying Beads__

Big Idea: Many important practical and mathematical applications involve comparing quantities of one kind or another; it is important to know which method to use and how we should use them.

Essential Question: How can I use a unit rate to make a prediction?

Notes from the class

Vocabulary

-Rate - A comparison of the quanities of two different units or objects -Unit Rate - A rate that compares an amount to a single unit. -Equation - A rule containing variables that represent a mathematical relationship.

Methods and Strategies discussed in class:

-Divide the first number of a rate by the second number of a rate to get the unit rate of it -Put the unit rate with the first rate number’s variable, the second rate number’s variable and a equal sign to make an equation

Questions for this problem’s unit:


 * 1) When are unit rates used?
 * 2) <span style="font: normal normal normal 14px/normal Helvetica; letter-spacing: 0px;">When are unit rates used for equations?

<span style="font: normal normal normal 14px/normal Helvetica; letter-spacing: 0px; margin: 0px;">__Problem 4.4__

<span style="font: normal normal normal 14px/normal Helvetica; letter-spacing: 0px; margin: 0px;">**Write an equation relating the cost (c) and the number of beads (x) for each type of bead:**

<span style="display: inline !important; font: normal normal normal 14px/normal Helvetica; letter-spacing: 0px; margin: 0px;">Spheres: c=0.6x



Cubes: c=0.8x



Cylinders: c=0.8x



__4.4 Follow Up__

**For each type of beads, you could find two unit rates. You could find the number of beads for each unit of cost (in other words, for each cent), and you could find the cost for each bead.**

1.**Which unit rate would be most useful if you were trying to figure out the number of beads you could buy with a certain number of money?**

A: It would be the unit rate for finding the number of beads for each unit of cost.

2.**Which unit rate would be most useful if you were trying to figure out how much money a certain number of beads cost?**

A: It would be the unit rate for finding the cost for each bead.

http://www.aaaknow.com/rat-unit-rate.htm

http://www.aaaknow.com/equ725x2.htm