Answer:
9 cows and 15 ducks
Step-by-step explanation:
step 1: create a system of equations, using the variable c for cows and d for ducks.
step 2: solve for d in the first equation, then plug it into the second, so that we can solve for c.
step 3: solve for c
step 4: now that we know what c is, plug c back into the first equation, and solve for d
step 5: solve for d, which gives you 15 ducks. We found c in step 3, which is 9 cows.