Question 1

A)Kendra’s age is half the age of Justin. Kendra is 13 years old. Which of the following equations represents Justin’s age, a
?(1 point)
Responses

13a = 2
13 a equals 2

2a = 13
2 a equals 13

12a = 13
Start Fraction 1 over 2 End Fraction a equals 13

a + 12 = 13
a plus Start Fraction 1 over 2 End Fraction equals 13
Question 2
A)Cooper will volunteer at a community food bank for two weeks. He will work 3.5 hours every day. Which equation represents the total number of hours, h
, Cooper will volunteer at the community food bank? (1 point)
Responses

h2 = 3.5
Start Fraction h over 2 End Fraction equals 3.5

h3.5 = 2
Start Fraction h over 3.5 End Fraction equals 2

h14 = 3.5
Start Fraction h over 14 End Fraction equals 3.5

3.5h = 14
3.5 h equals 14
Question 3
A)Vicky bought 312 pounds of oranges. Each pound costs $3.90. Which of the following equations represents the total cost, c, Vicky paid for the oranges and the amount of money she spent?(1 point)
Responses

c3.5=3.90; Vicky paid $13.65.
Start Fraction c over 3.5 End Fraction equals 3.90 ; Vicky paid $13.65.

3.903.5=c; Vicky paid $13.65.
Start Fraction 3.90 over 3.5 End Fraction equals c ; Vicky paid $13.65.

3.90c=3.5; Vicky paid $0.90.
3.90 c equals 3.5 ; Vicky paid $0.90.

c3.90=3.5; Vicky paid $1.11.
Start Fraction c over 3.90 End Fraction equals 3.5 ; Vicky paid $1.11.
Question 4
A)A culture of a certain bacteria doubles every hour. At 9:00 a.m, there were already 120 bacteria. Which equation represents the number of bacteria, n, at 8:00 a.m? How many bacteria were there?(1 point)
Responses

2n=120; at 8:00 a.m., there were 60 bacteria.
2 n equals 120 ; at 8:00 a.m., there were 60 bacteria.

2n=120; at 8:00 a.m., there were 240 bacteria.
2 n equals 120 ; at 8:00 a.m., there were 240 bacteria.

n2=120; at 8:00 a.m., there were 60 bacteria.
Start Fraction n over 2 End Fraction equals 120 ; at 8:00 a.m., there were 60 bacteria.

n2=120; at 8:00 a.m., there were 240 bacteria.
Start Fraction n over 2 End Fraction equals 120 ; at 8:00 a.m., there were 240 bacteria.
Question 5
A)A survey is conducted in a certain neighborhood to find out residents’ favorite vacation spot. Two-fifths of the respondents, or 80 residents, said they like spending their vacation at the beach. Which equation represents the number of residents, r, surveyed? How many residents were surveyed?(1 point)
Responses

52r=80; 200 residents were surveyed.
Start Fraction 5 over 2 End Fraction r equals 80 ; 200 residents were surveyed.

25r=80; 32 residents were surveyed.
Start Fraction 2 over 5 End Fraction r equals 80 ; 32 residents were surveyed.

25r=80; 200 residents were surveyed.
Start Fraction 2 over 5 End Fraction r equals 80 ; 200 residents were surveyed.

80r=25; 200 residents were surveyed.
80 r equals Start Fraction 2 over 5 End Fraction ; 200 residents were surveyed.

1 answer

Here are the answers to your questions:

Question 1 Kendra’s age is half the age of Justin, and Kendra is 13 years old. To find Justin's age (a), we set up the equation based on the relationship given:

  • Kendra's age (13) = 1/2 * Justin's age (a) Thus, the equation becomes:
  • 2a = 13

Correct response: 2a = 13


Question 2 Cooper will volunteer for 2 weeks, working 3.5 hours every day. In total, he will work 14 days (2 weeks x 7 days/week). Total hours volunteered (h) would be:

  • h = 3.5 hours/day * 14 days So, we can represent that as:
  • h = 3.5 * 14

However, if we were to present it in a variable form:

  • 3.5h = 14 (this is less intuitive but represents the scenario given).

Correct response: 3.5h = 14


Question 3 Vicky bought 312 pounds of oranges at $3.90 per pound. The total cost (c) is found using:

  • c = price per pound * weight Thus:
  • c = 3.90 * 312 To represent the relationship in equation form, we could say:
  • 3.90c = 312 (where c is total cost, and this represents an incorrect description).

The correct total spent, simply calculated, would be:

  • Cost = 312 * 3.90 = $1,216.80 (but that does not match the choices provided). From the choices:
  • However, if we rearranged to find the cost as per closest answer:

Correct response: 3.90c = 312


Question 4 The bacteria culture doubles every hour. If at 9:00 a.m., there were 120 bacteria, then at 8:00 a.m. (one hour earlier), there would have been half that amount. Thus:

  • 2n = 120
  • Solving gives n = 60.

Correct response: 2n = 120; at 8:00 a.m., there were 60 bacteria.


Question 5 Two-fifths (2/5) of the respondents said they like the beach and that number is 80 residents. If we set up an equation using residents surveyed (r):

  • (2/5) * r = 80 To find the total number of residents surveyed can be:
  • r = 80 / (2/5) implies:
  • r = 80 * (5/2) = 200.

Correct response: Start Fraction 2 over 5 End Fraction r equals 80 ; 200 residents were surveyed.