8 chickens and 12 ducks.
Let c represent the number of chickens. Let d represent the number of ducks.
The total number of animals bought was 20.
So c + d = 20.
The man received a $2 discount per chicken and a $0.50 discount per duck. The total
discount he received was $22.
So 2c + 0.50d = 22.
Now we have two equations with two varaibles. First we will rewrite the first
equation to find the value of c.
c + d = 20
c = 20 - d
Now we can substitue the vale of c from above into the second equation and solve
for d.
2c + 0.50d = 22
2(20 - d) + 0.50d = 22
40 - 2d + 0.50d = 22
40 - 1.50d = 22
-1.50d = -18
d = 12
Now solve for c in the first equation.
c + d = 20
c + 12 = 20
c = 8
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