Use binomial distribution, with p=0.20, n=20, x=3
P(X=x)=C(n,x)p^x (1-p)^(n-x)
P(X>=3)
=1-(P(X=0)+P(X=1)+P(X=2))
=1-(C(20,0)0.2^0 (0.8)^(20-0)+C(20,1)0.2^1 (0.8)^(20-1)+C(20,2)0.2^2 (0.8)^(20-2))
=1-(0.0115292+0.057646+0.136909)
=1-0.206085
=0.793915
The ratio of red to green is 2:5
Since ZY bisects GE and XY bisects EF, and both ZY and XY both bisect GF, then XY ~ ZE and ZY ~ XE.
Therefore ZE = XY = 5
And GE = 2× ZE (because bisected segments are = and therefore ×2 = long segment).
So GE = 2ZE = 2×5 = 10
Easiest method solving 2 unknowns is Substitution.
So there will normally be 2(ormore)equations given.
Say
X+Y= a
bX=cY + d
a b c d are numbers they give
So first we rearrange the first equation
X = a - Y
No we substitute this into the 2nd equation so that we can get Y
since we know X = a-Y,
b(a-Y) = cY + d
we rearrange and we can find Y for this, it is just Y and numbers
hence finding Y, we sub the value for Y into X = a-Y and we get X also .
By the size , color, or if they have wings or no wings, etc. just think of what might be different on each one or group.