Lincoln visited a farm where he saw some cows and ducks. There were 75 of them. He then counted the legs of the animals and found that there were 220. How many animals of each type were there in the farm?
Solution
If we assume all the animals were ducks
75 animals x 2 legs ----- 150 legs
But there were 220 legs. A cow has 2 “more legs” than a duck.
220 legs – 150 legs ----- 70 “more legs”
2 “more legs” ----- 1 cow
1 “more leg” ----- 1 divided by 2 = ½
70 “more legs” ----- ½ x 70 = 35
If there were 35 cows, the number of ducks were
75 – 35 = 40
Answer: There were 35 cows and 40 ducks.
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