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 = 7
y = 320x
b.
x + 7y = 320
y = 7x
c.
x – y = 320
y = 7x
d.
x + y = 320
y = 7x