SBAC Grade 8 Math Practice Test 1 — Questions and Answers
Question 1: The total length of the world's coastlines is about 315,000 miles. Which answer expresses this in scientific notation?
- 3.15×〖10〗^(-6)
- 3.15×〖10〗^(-5)
- 3.15×〖10〗^6
- 3.15×〖10〗^5 (Correct answer)
Correct answer: 3.15×〖10〗^5
Scientific notation expresses a number as a product of a number between 1 and 10 and a power of 10. To convert 315,000, move the decimal point from the end of the number to after the first non-zero digit (3). The decimal point moves 5 places to the left, so the exponent of 10 is 5, resulting in 3.15 Ă— 10^5.
Question 2: John’s Gym charges its members according to the equation C=40m where m is the number of months and C represents the total cost to each customer after m months. Ralph’s Recreation Room charges its members according to the equation C=45m. What relationship can be determined about the monthly cost to the members of each company?
- John’s monthly membership fee is equal to Ralph’s monthly membership fee.
- John’s monthly membership fee is more than Ralph’s monthly membership fee.
- John’s monthly membership fee is less than Ralph’s monthly membership fee. (Correct answer)
- No relationship between the monthly membership fees can be determined.
Correct answer: John’s monthly membership fee is less than Ralph’s monthly membership fee.
In the given equations, C=40m for John's Gym and C=45m for Ralph's Recreation Room, the coefficient of 'm' represents the monthly membership fee. For John's Gym, the monthly fee is $40, and for Ralph's Recreation Room, it is $45. Since $40 is less than $45, John's monthly membership fee is less than Ralph's.
Question 3: Which of the following graphs is not a function?
- A.
- B.
- C.
- D. (Correct answer)
Correct answer: D.
A graph represents a function if it passes the vertical line test, meaning any vertical line drawn through the graph intersects it at most once. Graph D fails this test because a vertical line can intersect it at multiple points. This indicates that for a single x-value, there are multiple y-values, which is not permitted in a function.
SBAC Grade 8 Math Practice Test 1
The total length of the world's coastlines is about 315,000 miles.
Which answer expresses this in scientific notation?