If the farm has 30 chickens and cows, and there are 82 chicken and cow legs all together, then how many chickens and how many cows could the farm have

The number of chicken and cows should be 19 and 11.

Given that,

Based on the above information, the calculation is as follows:

x + y = 30

Since a chicken has 2 legs and a cow has 4 legs.

So,  

2x + 4y = 82 - - - - - - - - - - - - 1

Now  

Substituting x = 30 - y into equation 1, it becomes

2(30 - y) + 4y = 82

60 - 2y + 4y = 82

- 2y + 4y = 82 - 60

2y = 22

y = 11

Now

x = 30 - 11

= 19

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there are 11 cows

Step-by-step explanation:

Let x represent the number of chickens in the farm.

Let y represent the number of cows in the farm.

If the farm has 30 chickens and cows, this means that

x + y = 30

There are 82 chicken and cow legs all together. A chicken has 2 legs. A cow has 4 legs. This means that

2x + 4y = 82 - - - - - - - - - - - - 1

Substituting x = 30 - y into equation 1, it becomes

2(30 - y) + 4y = 82

60 - 2y + 4y = 82

- 2y + 4y = 82 - 60

2y = 22

y = 22/2 = 11

Substituting y = 11 into x = 30 - y, it becomes

x = 30 - 11 = 19

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.