Transcript Ex. #6: Answers

2-Step Equation
Real-World Problems
WORD PROBLEM STEPS
1.) Thinking/Analyzing:
 Read problem carefully; highlight key facts.
 Write down what you are being asked to find
or solve for; the question is a clue.
 If stuck, make a list of what you do know.
 Drawing a picture often helps clarify.
2.) Define the variable.
3.) Write the equation.
Examples:
x = # of shirts
c = cost of a sweater
4.) Solve the equation.
5.) Check your work by substituting the solution
for the variable back in the equation.
6.) Answer the question(s) asked with a sentence.
Real World Problems
Ex. #1:
A company charges $2 for each balloon
in an arrangement and a $3 delivery fee.
You have $9 to spend. How many
balloons can you purchase?
Example #1
Let x = # of balloons
Words: (cost of 1 balloon)( times) (# of balloons)(plus) (cost of delivery)(equals) (total spent)
$2.00
*
x
+
2.00x + 3 = 9
-3 =-3
2.00x = 6
2.00
2.00
x=3
You can purchase 3 balloons.
$3
=
$9
Real World Problems
Ex. #2:
Mia had her birthday party at the
movies. It cost $27 for pizza and
$8.50 per friend for the movie
tickets. How many friends did Mia
have at her party if she spent a total
of $78?
Example #2
Let x represent # of friends
Words: (cost of 1 friend) ( times) (# of friends)
spent)
$8.50
*
x
(plus)
+
(cost of pizza) (equals) (total
$27
8.50x + 27 = 78
- 27 = - 27
8.50x = 51
8.50
8.50
x=6
Mia can have 6 friends at her party.
=
$ 78
Real World Problems
Ex. #3:
Cristiano is saving money to buy a
new bike that costs $189. He has
saved $99 so far. He plans on saving
$10 each week. In how many weeks
will he have enough money to buy
the bike?
Example #3
Ex. # 3: Answer
Define the variable: x = # of weeks
Equation: $10x + $99 = $189
x = 9 weeks
Cristiano will have enough money
for the bike in 9 weeks.
Real World Problems
Ex. #4:
Jennifer wants to buy some CDs that
cost $14 each, and a DVD that costs
$23. Write and solve an equation to
find out how many CDs she can buy.
Example 4
Ex. #4: Answer
Define the variable: x = # of CDs
Equation: 14x + 23 = 65
x = 3 CDs
Jennifer can buy 3 CDs.
Real World Problems
Ex. #5:
Kittens weigh about 100 grams when
born and gain 7 to 15 grams per day.
If a kitten weighed 100 grams at
birth and gained 8 grams per day, in
how many days will the kitten triple
its weight?
Example 5
Ex. #5: Answer
Define the variable: x = # of days
Equation: 8d + 100 = 300
x = 25
The kitten will triple its weight in
25 days.
Real World Problems
Ex. #6:
Room temperatures range from 20º C
to 25º C. Find the range of room
temperatures in Fº. Use the formula
F – 32 =1.8 C to convert from the
Celsius scale to the Fahrenheit scale.
Example 6
Ex. #6: Answers
F – 32 = 1.8(20); F = 68
F – 32 = 1.8(25); F = 77
Room temperatures range from 68
to 77º F.
Real World Problems
Ex. #7:
Luis’s cell phone plan costs $39 per
month. Text messages cost an
additional $0.15 each. If Luis’s cell
phone bill last month totaled $55.05,
how many text messages did he
send?
Example 7
Ex. #7: Answers
Define the variable: x = # of text
messages
Equation: $0.15x + 39 = $55.05
x = 107 text messages
Luis sent 107 text messages last
month.