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14. (08.06 LC)
An unknown number y is 20 more than an unknown number x. The number y is also x less than 2. The equations to find x and y are shown below:

y = x + 20
y = –x + 2

Which is a correct step to find x and y? (1 point)


Multiply the equations to eliminate y.
Add the equations to eliminate x.
Write the points where the graphs of the equations intersect the x-axis.
Write the points where the graphs of the equations intersect the y-axis.
15. (08.06 MC)
Katie and Pamela put some money into their money boxes every week. The amounts of money (y), in dollars, in their money boxes after certain amounts of time (x), in weeks, are shown by the equations below:

Katie
y = 30x + 20

Pamela
y = 20x + 90

After how many weeks will Katie and Pamela have the same amount of money in their money boxes, and what will that amount be? (1 point)


6 weeks, $150
6 weeks, $230
7 weeks, $150
7 weeks, $230
16. (08.06 MC)
A zoo train ride costs $4 per adult and $1 per child. On a certain day, the total number of adults (a) and children (c) who took the ride was 27, and the total money collected was $60. What was the number of children and the number of adults who took the train ride that day, and which pair of equations can be solved to find the numbers? (1 point)


11 children and 16 adults
Equation 1: a + c = 27
Equation 2: 4a + c = 60
16 childrenand 11 adults
Equation 1: a + c = 27
Equation 2: 4a + c = 60
11 children and 16 adults
Equation 1: a + c = 27
Equation 2: 4a – c = 60
16 childrenand 11 adults
Equation 1: a + c = 27
Equation 2: 4a – c = 60

Respuesta :

kphung76127
14. B Add the equations
Since the equations have x and -x, if you add, it cancels out to 0 and x will be eliminated.

15. 7 weeks, $230 D
30x+20=20x+90
10x+20=90
10x=70
x=7

Plug x in
y=20(7)+90
y=140+90
y=230

16. B
4a+c= 60
a+c=27

16 children and 11 adults since 11+16=27 and 4(11)+16= 44+16=60

Answer:

14) Add the equations to eliminate x.

15)7 weeks, $230

16)11 children and 16 adults

Equation 1: a + c = 27

Equation 2: 4a + c = 60

Step-by-step explanation:

14) To find x and y in the given equations :

y = x + 20

y = –x + 2

Our first step will be to add the two equations so that x is eliminated and we can find y . The option

Add the equations to eliminate x is the correct option.

15)  The given equations are Katie

y = 30x + 20

Pamela

y = 20x + 90

y represents the amount of money in dollars and x represents the amount of time in weeks ,

Using substitution method we have :

30x+20=20x+90

Or 30x-20x=90-20

10x=70 or

x=7 .

Substituting x value in y=30x+20 we  have:

y=30(7)+20

y= 210+20

y=230.

The correct option is 7 weeks, $230.

16) It is given  the total number of adults (a) and children (c)  is 27,

or a+c=27.

Given zoo train ride costs $4 per adult and $1 per child,

Or 4a+c=60.

Subtracting the two equations we have:

4a+c=60

a+c=27

-    -    -

....................................

3a =33,

Or a=11.

Substituting a value in a+c=27

11+c=27

or c=16.

The correct option is

11 children and 16 adults

Equation 1: a + c = 27

Equation 2: 4a + c = 60

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