Question

What is the equation for 4 times the number of cows plus 2 times the number of ducks is 20

Answer 1

Let
`c,d` be the number of cows and ducks, respectively.

So, 4 times the number of cows is 4c, and 2 times the number of ducks is 2d. Together, they are
`4c+2d`

This has to equal 20, so the equation is

`4x+2d=20`