Answer:
Answer of question 1 :
Explanation:
Let x be the legs of ducks
And y be the legs of cows
According to the question,
2x + 4y = 52...…..(i) ( as ducks ahs two legs and as cows has 4 legs)
As he has 21 animals in total so,
x + y = 21...…..(ii)
We have make the equation. We will solve them by eliminatory method or substitution method. Here, I'll go for substitution method.
From equation (ii)
x = 21 - y....…..(iii)
Putting the value of x in equation (i),
2x + 4y = 52
2( 21 - y ) + 4y = 52
42 - 2y + 4y = 52
2y = 52 - 42
y = 10/2
y = 5 ( He has 2 cows)
putting the value of y in equation (ii)
x + y = 21
x + 5 = 21
x = 21 -5
x = 16 ( He has 16 ducks)
Answer:
14
Explanation:
For independent variables X and Y;
S.D(X - Y) is expanded as :
S.D(X) + S.D(Y)
If S.D(X) = 6 and S.D(Y) = 8 ; where, X and Y are independent ;
SD(X-Y) = SD(X) + SD(Y)
SD(X - Y) = 6 + 8
SD(X - Y) = 14
10000 I believe that is the answer
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