15 points! please answer all questions

1. Choose the correct answer.

Elena bought 320 tropical fish for a museum display. She bought 7 times as many triggerfish as parrotfish. How many of each type of fish did she buy?

Which is a system of equations to model the problem if x represents the number of parrotfish Elena bought and y represents the number of triggerfish she bought?


A.
x + y = 320
y = 7x

B.
x + 7y = 320
y = 7x

C.
x – y = 320
y = 7x

D.
x + y = 7
y = 320x

2. Michael and Kathryn bowl together and their combined total score for one game was 425 points. Michael’s score was 70 less than twice Kathryn’s. What were their scores?

Which is a system of equations to model the problem if x represents Kathryn’s score and y represents Michael’s score?

A.
x + y = 70
y = 2x – 425

B.
x – y = 425
y = 2x – 70

C.
x + y = 425
y = 2x – 70

D.
x + y = 425
y = 2x + 70

3. David has a hose that is 27 ft long. He wants to cut it into two pieces so that the longer piece is 3 ft more than 2 times the length of the shorter piece.

How long will each piece of hose be?

Shorter piece:______ft
Longer piece:______ ft

4. Admission for a movie is $8 for children and $12 for adults. On a certain day, 3200 people attend the movie theater and $33,040 is collected.

How many children and how many adults attended the movies?

children.__?____
adults.____?____

5.A collection of quarters and dimes is worth $12.40. There are 67 coins in all.

How many of each coin are there?

quarters.___?_____
dimes.___?____





Answer :

1. A.
x parrot fish + y triggerfish = 320 total fish. 
y = 7x shows that there are 7 times as many triggerfish.
2. C
x + y shows a total score of 425.
y = 2x - 70 shows that Michael's score, y, is 70 less (minus) than twice Kathryn's 
3. write two equations
x + y = 27 total feet
2x + 3 = y
Substitute 2x + 3 for y in the first equation
x + (2x + 3) = 27
3x + 3 = 27
3x = 24
x = 8
Substitute 8 in to either equation to find the other length.
8 + y = 27
y = 19
The shorter piece is 8 and the longer piece is 19
4. x + y = 3200 people -> y = 3200-x
8x + 12y = 33,040 dollars
8x + 12(3200 - x) = 33040
8x + 38400 - 12x = 33040
-4x = -5360
x = 1340 (1340 children)
1340 + y = 3200
y = 1860 adults
5. I don't think the numbers for this were put in correctly because I get a decimal and a negative number when I solve for it but hopefully if you do get the correct cost/amount of coins you will understand this well enough to do it on your own. Hope I helped!