This is like the equivalent to a jar with 4 green balls and 6 white balls, where you are picking 3. (The 4 green balls signify the friends from kindergarten.)
You want to solve the probability that the first two balls are green and the third is white.
First draw --> 4 green out of 10 balls --> 4/10 = 2/5
Second draw --> 3 green out of 9 balls --> 3/9 = 1/3
Third draw --> 6 white out of 8 balls --> 6/8 = 3/4
2/5 x 1/3 x 3/4
= 6/60
= 1/10
so the answer is 1/10 (or 10%)
Answer:
here (edit I made a mistake)
Step-by-step explanation:
9) 
10) y = x - 3
11) 
12) 
these are the slop int forms, my bad...
sorry
Answer: N=800/5
N=160
He needs to save $160 every week to get $800 in 5 weeks
hope this helps.
Answer:
400 m^2.
Step-by-step explanation:
The largest area is obtained where the enclosure is a square.
I think that's the right answer because a square is a special form of a rectangle.
So the square would be 20 * 20 = 400 m^2.
Proof:
Let the sides of the rectangle be x and y m long
The area A = xy.
Also the perimeter 2x + 2y = 80
x + y = 40
y = 40 - x.
So substituting for y in A = xy:-
A = x(40 - x)
A = 40x - x^2
For maximum value of A we find the derivative and equate it to 0:
derivative A' = 40 - 2x = 0
2x = 40
x = 20.
So y = 40 - x
= 40 - 20
=20
x and y are the same value so x = y.
Therefore for maximum area the rectangle is a square.