Answer:
The expression for the perimeter of the rectangle is: 
Step-by-step explanation:
Perimeter of a rectangle:
A rectangle has length l and width w. It's perimeter is given by:

In this question:

So

The expression for the perimeter of the rectangle is: 
Answer:
1 . 24
2. 21
Step-by-step explanation:
1.
b=6
h=4
A= b*h
=6*4
=24
2. b=6
h= 7
A= 1/2*b*h
= 1/2*6*7
=21
The answer is none of these
Let X = the 29% alloy and Y = the 60% alloy.
They want a total of 80kg, so you have X +Y = 80
Rewrite that to get X = 80-Y
You also want 0.20X + 0.60Y = 0.52(80)
Replace X with 80-y:
0.20(80-y) + 0.60y = 0.52(80)
Simplify:
16 - 0.20y + 0.60y = 41.6
Combine like terms:
16 +0.40y = 41.6
Subtract 16 from each side:
0.40y = 25.6
Divide both sides by 0.40
y = 25.6 / 0.40
y = 64
Now you have Y replace y with 80 in X = 80-Y
X = 80 - 64
X = 16
They need 64 Kg of the 60% alloy and 16 Kg of the 20% alloy.
Let the boy be B and the girl be G
there are six possible outcomes
BGG, GBB, GBG, BGB, BBB, and GGG
therefore the probability of getting one boy and two girls is

also the probability of getting 3 girls is