# 9.1 Use a problem solving strategy  (Page 3/6)

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Guillermo bought textbooks and notebooks at the bookstore. The number of textbooks was $3$ more than the number of notebooks. He bought $5$ textbooks. How many notebooks did he buy?

2

Gerry worked Sudoku puzzles and crossword puzzles this week. The number of Sudoku puzzles he completed is seven more than the number of crossword puzzles. He completed $14$ Sudoku puzzles. How many crossword puzzles did he complete?

7

In Solve Sales Tax, Commission, and Discount Applications , we learned how to translate and solve basic percent equations and used them to solve sales tax and commission applications. In the next example, we will apply our Problem Solving Strategy to more applications of percent.

Nga's car insurance premium increased by $\text{60},$ which was $\text{8%}$ of the original cost. What was the original cost of the premium?

## Solution

 Step 1. Read the problem. Remember, if there are words you don't understand, look them up. Step 2. Identify what you are looking for. the original cost of the premium Step 3. Name. Choose a variable to represent the original cost of premium. Let $c=\text{the original cost}$ Step 4. Translate. Restate as one sentence. Translate into an equation. Step 5. Solve the equation. Divide both sides by 0.08. Simplify. $c=750$ Step 6. Check: Is our answer reasonable? Yes, a $750 premium on auto insurance is reasonable. Now let's check our algebra. Is 8% of 750 equal to 60? Step 7. Answer the question. The original cost of Nga's premium was$750.

Pilar's rent increased by $\text{4%}.$ The increase was $\text{38}.$ What was the original amount of Pilar's rent?

$950 Steve saves $\text{12%}$ of his paycheck each month. If he saved $\text{504}$ last month, how much was his paycheck?$4,200

## Solve number problems

Now we will translate and solve number problems . In number problems, you are given some clues about one or more numbers, and you use these clues to build an equation. Number problems don't usually arise on an everyday basis, but they provide a good introduction to practicing the Problem Solving Strategy . Remember to look for clue words such as difference , of , and and .

The difference of a number and six is $13.$ Find the number.

## Solution

 Step 1. Read the problem. Do you understand all the words? Step 2. Identify what you are looking for. the number Step 3. Name. Choose a variable to represent the number. Let $n=\text{the number}$ Step 4. Translate. Restate as one sentence. Translate into an equation. Step 5. Solve the equation. Add 6 to both sides. Simplify. Step 6. Check: The difference of 19 and 6 is 13. It checks. Step 7. Answer the question. The number is 19.

The difference of a number and eight is $17.$ Find the number.

25

The difference of a number and eleven is $-7.$ Find the number.

4

The sum of twice a number and seven is $15.$ Find the number.

## Solution

 Step 1. Read the problem. Step 2. Identify what you are looking for. the number Step 3. Name. Choose a variable to represent the number. Let $n=\text{the number}$ Step 4. Translate. Restate the problem as one sentence. Translate into an equation. Step 5. Solve the equation. Subtract 7 from each side and simplify. Divide each side by 2 and simplify. Step 6. Check: is the sum of twice 4 and 7 equal to 15? Step 7. Answer the question. The number is 4.

can someone help me with some logarithmic and exponential equations.
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
a perfect square v²+2v+_
kkk nice
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
rolling four fair dice and getting an even number an all four dice
Kristine 2*2*2=8
Differences Between Laspeyres and Paasche Indices
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
is it 3×y ?
J, combine like terms 7x-4y
im not good at math so would this help me
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
how do you translate this in Algebraic Expressions
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?