The distance from Kara’s house to school is 20 miles. If she drives between 40 and 60 miles per hour as she travels from her house to school, what is the least number of minutes it will take her to arrive?

A. 15 minutes
Incorrect. Use the formula d=rt to calculate the time it will take for Kara to arrive.

B. 20 minutes
Correct!

C. 30 minutes
Incorrect. Use the formula d=rt to calculate the time it will take for Kara to arrive. For the least number of minutes, use 60 mph for the rate since this is the maximum speed she travels.

D. 40 minutes
Incorrect. Use the formula d=rt to calculate the time it will take for Kara to arrive. For the least number of minutes, use 60 mph for the rate since this is the maximum speed she travels.

There are 16 homeroom classes and 228 students at Faulkner Ninth Grade Campus. The equation 16s = 228 can be used to determine s, the mean number of students per homeroom. Based on the solution s = 14.25, which of the following statements could be true?

A. There are 9 homerooms with 12 students each and 7 homerooms with 16 students each.
Incorrect. If there were 9 homerooms with 12 students and 7 homerooms with 16 students, the sum of the students would be 220 students, not 228 students.

B. There are 16 homerooms with 14 students each.
Incorrect. 16 homerooms with 14 students accounts for only 224, not 228 students.

C. There are 16 homerooms with 15 students each.
Incorrect. 16 homerooms with 15 students accounts for 240, not 228 students.

D. There are 7 homerooms with 12 students each and 9 homerooms with 16 students each.
Correct! 7 homerooms with 12 students and 9 homerooms with 16 students sums to 228 students. The mean number of students per homeroom is 228 divided by 16, or 14.25 students per homeroom.

Ginger plans to go snow skiing over spring break. She is trying to decide whether to buy or rent her skis. The prices for each are shown below.

Ginger believes if she skis for 11 days, then it would cost the same to rent or buy the skis. Is her conclusion reasonable?

A. No, because if x represents the number of days Ginger skis, then 15 − x = 11, or 15 − 4 = 11.
Incorrect. If Ginger buys the skis, she would pay $165, which is the same amount as renting the skis for 11 days at $15 per day.

B. No, because if x represents the number of days Ginger skis, then 15x = 45, or 15(3) = 45.
Incorrect. If Ginger buys the skis, she would pay $165, which is the same amount as renting the skis for 11 days at $15 per day.

C. Yes, because if x represents the number of days Ginger skis, then 15x = 165, or 15(11) = 165.
Correct! If Ginger pays $15 per day for 11 days, then the cost to rent would be 15(11), or $165, which is the same as the cost to purchase the skis.

D. Yes, because if x represents the number of days Ginger skis, then 15 + x = 165, or 15 + 11 = 165.
Incorrect. If Ginger pays $15 per day for 11 days, then she should calculate the cost by multiplying 15 and 11.

Mr. Martin had $175 in his library account. He bought new books for the autobiography section. Each book cost $12. The amount of money remaining in the account, a, can be represented by the function a = 175 – 12b, where b represents the number of books that he purchased. What is the maximum number of books Mr. Martin can purchase for the autobiography section of his library?

A. 12
Incorrect. If the amount of money remaining in the account is a = 175 – 12b and b = 12, then a = 175 – 12(12) or 31. Therefore, Mr. Martin can afford to buy more than 12 books.

B. 14
Correct! If the amount of money remaining in the account is a = 175 – 12b and b = 14, then a = 175 – 12(14) or 7.

C. 15
Incorrect. If the amount of money remaining in the account is a = 175 – 12b and b = 15, then a = 175 – 12(15) or -5. Therefore, Mr. Martin cannot afford to buy 15 books.

D. 16
Incorrect. If the amount of money remaining in the account is a = 175 – 12b and b = 16, then a = 175 – 12(16) or -17. Therefore, Mr. Martin cannot afford to buy 16 books.

Ms. Yanez plans to order rose bushes for her flowerbeds. The bushes cost $7.50 each and the shipping charge is $4.00, regardless of the number of bushes ordered.

Ms. Yanez budgeted $60.00 for the rose bushes. She believes that the maximum number of rose bushes she can order is 8. Is her conclusion reasonable?

A. No, because if x represents the number of rose bushes, then the total charge is 7.50x + 4, or 7.50(8) + 4, or $64.
Correct! If Ms. Yanez pays $7.50 per bush for 8 bushes and $4 shipping, then the total charge is $64, which is more than the $60 she budgeted.

B. No, because if x represents the number of rose bushes, then the total charge is 7.50x, or 7.50(4), or $30.
Incorrect. Ms. Yanez believes the maximum number of rose bushes she can order is 8, which would yield a charge of 7.50(8) + 4, or $64.

C. Yes, because if x represents the number of rose bushes, then the total charge is 4x + 7.50, or 4(8) + 7.50, or $39.50.
Incorrect. Ms. Yanez would pay $7.50 per rose bush and $4.00 shipping.

D. Yes, because if x represents the number of rose bushes, then the total charge is 7.50x, or 7.50(8), or $60.
Incorrect. Ms. Yanez must also include the cost of shipping.