To find the diameter, you use the formula: 2x. we use 2x because the radius is 2 times the diameter.
so, if the radius is 3,980, then we substitute that into the formula.
2(3,980)
this will give us 7960. the diameter is 7960 miles.
A)
Let x represent the cost of 1 student, and y the cost of 1 teacher.
B)
In the first group, there's 25 students and 2 teachers. Their total cost is $97.50
So 25x + 2y = 97.50
In the second group, there's 32 students and 3 teachers. Their total cost is $127
So 32x + 3y = 127
We get the following system of equations:
25x + 2y = 97.50 (1)
32x + 3y = 127 (2)
C)
25x + 2y = 97.50 (1)
32x + 3y = 127 (2)
In equation (1)
25x + 2y = 97.50
25x + 2y - 2y = 97.50 - 2y
25x = 97.50 - 2y
25x / 25 = 97.50/25 - 2y/25
x = 3.9 - (2/25)y
In equation (2), let's replace x by its algebraic value
32x + 3y = 127
32(-2/25y + 3.9) + 3y = 127
11/25y + 124.8 = 127
11/25y + 124.8 - 124.8 = 127 - 124.8
11/25y = 2.2
(11/25y) / (11/25) = 2.2 / (11/25)
y = 5
x = -2/25y + 3.9
x = -2/25 * 5 + 3.9
x = 3.5
So the cost of each student is $3.5, and the cost of each teacher is $5.
Hope this helps! :)
Answer:
A
Step-by-step explanation:
Because you have to use the Pythagorean theorem to solve for this.
The number is = 10x+y
if reverse the digits, the number is: 10y+x
The sum fo its digits is = x+y=5
I suggest this system of equations:
(10y+x)-(10x+y)=27 ⇒9y-9x=27
x+y=5
We can solve this system of equations by equaliztion method
x=5-y
9y-9(5-y)=27
9y-45+9y=27
18y=27+45
18y=72
y=72/18
y=4
x=5-y
x=5-4=1
The number is: 10x+y=10(1)+4=14
Answer: the number is 14
