Probably C. 30 Hope this helps I might wrong sometimes
Answer:
The minimum of cows he needs are: 2
Step-by-step explanation:
There's a relation between each animal:
5 chickens equals 1 pig
3 pigs equals 2 sheep
5 sheep equals 2 cows
You can understand it as the following three abstractions:
5c = 1p (1)
3p = 2s (2)
5s = 2o (3)
Where:
c is for chickens
p is for pigs
s is for sheep
o is for cows
So now you have three equations with 4 variables. The next step is to obtain an equation that relates directly the variable c (chickens) with the variable o (cows). In order to do that from the equation 2 we obtain s in terms of p, as follow:

Then we replace s in the equation 3 and we obtain v in terms of p:


Now we replace v in the equation 1:

(4)
The equation 4 means that 1 chicken equals the fifteenth part of a cow. For this case the farmer needs 20 chikens, so we multiply per 20 each part of the equation 4:
As it is impossible to have 1.3333 cows, the answer is 2 cows approximately.
Number of 1/2-inch cubes length-wise = 8 1/2 ÷ 1/2 = 17
Number of 1/2-inch cubes width-wise = 5 1/2 ÷ 1/2 = 11
Number of 1/2-inch cubes height-wise = 2 1/2 ÷ 1/2 = 5
Number of 1/2-inch cubes = 17 x 11 x 5 = 935
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Answer: 935 1/2-inch cubes are needed.
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To add/subtract fractions you need to have a common denominator...
(2/2)(4n/15)+(5/5)(n/6)
8n/30+5n/30
(8n+5n)/30
13n/30
Answer:
14 floors
Step-by-step explanation:
The number of floors that the buliding contain,
(floors/windows) × number of the windows
; 2/18 × 126
; 2 × 7
; 14 floors