There are 4 more Muscovy ducks than Cayugas, and 3 more than twice as many Cayugas as Khaki Campbells. If there are 90 ducks total, how many Muscovies are there?
Let x represent the number of Khaki Campbell ducks.
Cayugas:3+2x
Muscovies:4+(3+2x)=7+2x
Total: x+3+2x+7+2x=90
5x+10=90
5x=80
x=<<16=16>>16
Muscovy: 7+2(16)=39
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