Question
At the park the other day I saw 22 ducks and dogs.I counted 60 legs.How many of the animals were ducks and how many were dogs?
Answers
Ms. Sue
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MathMate
You can choose to do the sum mentally as follows:
If all the animals were ducks, there would be 2*22=44 legs. Since there are (60-44)=16 more legs, there must be (16/2)=8 dogs, the rest (22-6)=14 ducks.
If you prefer to solve the sum mathematically, you would set up an equation as follows:
Let
k=number of ducks, then
22-k = number of dogs.
We have
2*k+4*(22-k)=60
Solve for k.
2k+88-4k=60
2k=88-60=28
k=14
So there are 14 ducks and (22-14)=8 dogs.
If all the animals were ducks, there would be 2*22=44 legs. Since there are (60-44)=16 more legs, there must be (16/2)=8 dogs, the rest (22-6)=14 ducks.
If you prefer to solve the sum mathematically, you would set up an equation as follows:
Let
k=number of ducks, then
22-k = number of dogs.
We have
2*k+4*(22-k)=60
Solve for k.
2k+88-4k=60
2k=88-60=28
k=14
So there are 14 ducks and (22-14)=8 dogs.