Elvin is twice as old as his sister Serena. Which equation can be used to find e, Elvin’s age, if s represents Serena’s age?
&anslation
F.
2 𝑠
= 𝑒
G. 𝑠 − 2 = 𝑒
H. 𝑠 + 2 = 𝑒
J. 2𝑠 = 𝑒
You are saving money for a class trip to Washington, D.C. You need t for the total for the trip. You have saved $278. You can save an additional $50 each month. What is the variable expression to represent the total amount of money you have saved after m months?
A.
278 + 50m=850
B.
278m + 50=850
C.
50m=850
D.
50 + m=850
You buy a book that is 540 pages long (l). You can read about 30 pages per hour. Which equation represents how long it will take you to (r), read the book.
F. l=
30 𝑟
G. 𝑙 = 𝑟 + 30
H. 𝑙 = 30𝑟
J. 30r = l
Student Checkpoint
A family of five people has a budget, b, to buy camping supplies.
The cost of each sleeping bag is s. Which equation can be used to solve the problem?
F. 5s = b
G. b= 5 + s
H. b= 5s
J. 5 + s = b
After touring a cave, you visit the gift shop and buy g, geodes.
Each geode costs $4.99. You have t, a total amount, you can spend. Which equation can be used to solve the problem?
A.
𝑔 = 4.99𝑡
B.
4.99𝑡 = 𝑔
C.
4.99𝑔 = 𝑡
D.
𝑡 = 4.99𝑔
Your family is going on a vacation. Your destination is 880 miles away. Your family is driving there at an average speed of s, miles per hour. What is the variable expression to represent t, the total amount of hours your family would have to drive?
F. 𝑡 =
880 𝑠 𝑠
G. 𝑡 =
880
H. 𝑡 = 880𝑠
J. 880𝑠 = 𝑡
4. You use an automated teller machine (ATM) to deposit a check for
$122.94 into your savings account. Your receipt from the ATM shows a balance of $286.59 after the deposit. Find the balance of your savings account before the deposit.
Bubble in the correct place value.
Writing Equations from Real
World Problems
6.6 (C) I will represent a given situation using verbal descriptions and equations.
STAAR QUESTION:
The cost of downloading one song from a website is $0.99.
Which equation can be used to find t, the cost in dollars of downloading n songs?
F. t = 0.99 + n
G. n = 0.99 + t
H. t = 0.99n
J. n = 0.99t
Ask yourself:
What is the total?
What is the variable?
Which operation do I write?
What’s the inverse operation to solve?
TEACHER EXAMPLE
The cost of downloading a book to your Kindle is 3.99. Which equation can be used to find d, the cost in dollars for downloading k , the number of books?
A.
𝑑 = 3.99 + 𝑘
B.
𝑑 = 3.99𝑘
C.
𝑘 = 3.99 + 𝑑
D.
𝑘 = 3.99𝑑