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Study Guides > Prealgebra

Using Decimals in Money Applications

Learning Outcomes

  • Translate expressions from a given scenario
  • Answer a question by using operations on decimals
  We often apply decimals in real life, and most of the applications involving money. The Strategy for Applications we used in The Language of Algebra gives us a plan to follow to help find the answer. Take a moment to review that strategy now.

Strategy for Applications

  1. Identify what you are asked to find.
  2. Write a phrase that gives the information to find it.
  3. Translate the phrase to an expression.
  4. Simplify the expression.
  5. Answer the question with a complete sentence.
 

example

Paul received [latex]$50[/latex] for his birthday. He spent [latex]$31.64[/latex] on a video game. How much of Paul’s birthday money was left? Solution
What are you asked to find? How much did Paul have left?
Write a phrase. [latex]$50[/latex] less [latex]$31.64[/latex]
Translate. [latex]50 - 31.64[/latex]
Simplify. [latex]18.36[/latex]
Write a sentence. Paul has [latex]$18.36[/latex] left.
 

try it

[ohm_question]146034[/ohm_question] [ohm_question]146035[/ohm_question]
   

example

Jessie put [latex]8[/latex] gallons of gas in her car. One gallon of gas costs [latex]$3.529[/latex]. How much does Jessie owe for the gas? (Round the answer to the nearest cent.)

Answer: Solution

What are you asked to find? How much did Jessie owe for all the gas?
Write a phrase. 8 times the cost of one gallon of gas
Translate. [latex]8\left($3.529\right)[/latex]
Simplify. [latex]$28.232[/latex]
Round to the nearest cent. [latex]$28.23[/latex]
Write a sentence. Jessie owes [latex]$28.23[/latex] for her gas purchase.

 

try it

[ohm_question]146036[/ohm_question] [ohm_question]146037[/ohm_question]
 

example

Four friends went out for dinner. They shared a large pizza and a pitcher of soda. The total cost of their dinner was [latex]$31.76[/latex]. If they divide the cost equally, how much should each friend pay?

Answer: Solution

What are you asked to find? How much should each friend pay?
Write a phrase. [latex]$31.76[/latex] divided equally among the four friends.
Translate to an expression. [latex]$31.76\div 4[/latex]
Simplify. [latex]$7.94[/latex]
Write a sentence. Each friend should pay [latex]$7.94[/latex] for his share of the dinner.

 

try it

[ohm_question]146039[/ohm_question] [ohm_question]146040[/ohm_question]
  Be careful to follow the order of operations in the next example. Remember to multiply before you add.  

example

Marla buys [latex]6[/latex] bananas that cost [latex]$0.22[/latex] each and [latex]4[/latex] oranges that cost [latex]$0.49[/latex] each. How much is the total cost of the fruit?

Answer: Solution

What are you asked to find? How much is the total cost of the fruit?
Write a phrase. [latex]6[/latex] times the cost of each banana plus [latex]4[/latex] times the cost of each orange
Translate to an expression. [latex]6\left($0.22\right)+4\left($0.49\right)[/latex]
Simplify. [latex]$1.32+$1.96[/latex]
Add. [latex]$3.28[/latex]
Write a sentence. Marla's total cost for the fruit is [latex]$3.28[/latex].

 

try it

[ohm_question]146047[/ohm_question] [ohm_question]146048[/ohm_question]
   

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