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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 . 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. ___?____

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