Answer:
2.93
Step-by-step explanation:
I guessed and got it right lol
Let n = number of nickels, and p = number of pennies.
The number of coins is 25, so we get this equation.
n + p = 25
The value of the coins is 0.05 per nickel, and 0.01 per penny.
0.05n + 0.01p = 0.73
Now you have a system of equations.
n + p = 25
0.05n + 0.01p = 0.73
Solve the first equation for n:
n = 25 - p
Now substitute into the second equation.
0.05(25 - p) + 0.01p = 0.73
1.25 - 0.05p + 0.01p = 0.73
-0.04p = -0.52
p = 13
There were 13 pennies.
Now we substitute 13 for p in n + p = 25 to find out the number of nickels.
n + 13 = 25
n = 12
There are 13 pennies and 12 nickels.
Check: 13 pennies and 12 nickels does total 25 coins.
13 * 0.01 + 12 * 0.05 = 0.13 + 0.60 = 0.73
The value is $0.73.
Our answer is correct.
<h3>
Answer: 1848 cubic meters</h3>
=================================================================
Explanation:
Imagine rotating the figure so that the triangular face is flat on the ground. This makes the triangular faces to be the floor and ceiling of this room.
The floor is a triangle with base 24 meters and height 7 meters. The floor area is base*height/2 = 24*7/2 = 84 square meters.
Multiply this floor area with the height of the room (22 m) to get the volume of the room.
volume = (floor area)*(height) = 84*22 = 1848 cubic meters
It costs $3.63 more for the gold die than the gold plated die.
The volume of each half of the die is given by the formula
V=1/3s³.
This means the total volume is V = 2(1/3s³) = 2(1/3(2³)) = 16/3 = 5.33 mm³.
For the solid gold die, we know that it weighs 0.02g per mm³:
5.33(0.02) = 0.1066g
Gold costs $40.38 per gram:
40.38(0.1066) = $4.30
For the plastic die, plastic weighs 0.01 g per mm³:
0.01(5.33) = 0.0533g
Plastic costs $10 per gram:
0.0533(10) = 0.533 ≈ $0.54.
We also need to find the surface area, as it will be painted. Each face is an equilateral triangle; the area of a triangle is given by the formula
A = 1/2bh
We need to use the Pythagorean theorem to find the height. The height will be one leg and 1/2 of the base will be the other; the slanted side will be the hypotenuse:
h² + (1/2(2))² = 2²
h² + 1² = 2²
h² + 1 = 4
h² = 3
h = √3
The area of the triangle would then be A = 1/2bh = 1/2(2)(√3) = √3. There are 8 such faces on the die, so the total surface area would be 8√3 = 13.86mm².
Paint costs $0.01 per mm²:
13.86(0.01) = 0.1386 ≈ $0.14
Together the cost for the plastic is 0.14+0.53 = $0.67.
The difference between it and the cost for the gold die is 4.30 - 0.67 = $3.63.
