We have a question: 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?
And an answer: 39
So how you got the answer?
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. Muscovy: 7 + 2(16) = 39.

We have a question: Trey has 7 times as many turtles as Kris. Kris has 1/4 as many turtles as Kristen has. How many more turtles does Trey have than Kristen, if Kristen has 12?
And an answer: 9
So how you got the answer?
Kris has 12 / 4 = 3 turtles. Trey has 3 * 7 = 21 turtles. Trey has 21 - 12 = 9 more turtles than Kristen.

We have a question: Stephen has 110 ants in his ant farm. Half of the ants are worker ants, 20 percent of the worker ants are male. How many female worker ants are there?
And an answer: 44
So how you got the answer?
Worker ants:110 / 2 = 55 ants. Male worker ants:55(.20) = 11. Female worker ants:55 - 11 = 44 ants.