Answer: there are 3 geese in the pond.
Step-by-step explanation:
Let x represent the number of ducks in the pond.
Let y represent the number of geese in the pond.
There are 19 birds in a pond, all which are ducks or geese. This means that
x + y = 19 - - - - - - - - - - - - - - -1
If the number of ducks in the pond is 1 more than twice the number of geese in the pond, it means that
x = 2y + 1
Substituting x = 2y + 1 into equation 1, it becomes
2y + 1 + y = 19
3y = 19 - 1 = 18
y = 18/3 = 6
x = 2y + 1 = 2 × 6 + 1
x = 13
