Step-by-step explanation:
Number for Breaststroke = 50
Number for Butterfly = 25
Ratio of Breaststroke to Butterfly
= 50 : 25 = 2 : 1.
The ratio value is 2/1.
Answer:
r=-6
Step-by-step explanation:
You want to know when both colleges have the same enrollment. "When" is a time thing so you are going to be solving for x. The number of students is the same and that means you will be solving for y.
Since both ys are equal, you can equate the right side of each equation to each other.
0.046 x + 0.570 = - 0.036x + 2.702 There are a number of ways to go on. The easiest is to dig out your calculator. Add 0.036x to both sides.
0.046x + 0.036x + 0.570 = 2.702
0.082x + 0.570 = 2.702 Now subtract 0.570 from both sides.
0.082x = 2.702 - 0.570
0.082x = 2.132 Divide by 0.084
x = 2.132 / 0.082
x = 26 which means you add 26 onto 1990. The year this took place was 2016
x = 2016 (That's the year there was equality in enrollment). The second one is the only year that gives 2016 as an answer. So you don't have to find y. But we'll do it anyway.
Now you have to solve for y
y = 0.046x +0.57 put 26 in for x
y = 0.046 * 26 + 0.570
y = 1.196 + 0.570
y = 1.766 enrollment numbers were equal, but this is in thousands.
y = 1766 enrollment in actual numbers of students.
Second choice <<<<<===== answer.
"The sum of two numbers is 20" can be translated mathematically into the equation:
x + y = 20.
"... and their difference is 10" can be translated mathematically as:
x - y = 10
We can now find the two unknown numbers, x and y, because we now have a system of two equations in two unknowns, x and y. We'll use the Addition-Subtraction Method, also know as the Elimination Method, to solve this system of equations for x and y by first eliminating one of the variables, y, by adding the second equation to the first equation to get a third equation in just one unknown, x, as follows:
Adding the two equations will eliminate the variable y:
x + y = 20
x - y = 10
-----------
2x + 0 = 30
2x = 30
(2x)/2 = 30/2
(2/2)x = 15
(1)x = 15
x = 15
Now, substitute x = 15 back into one of the two original equations. Let's use the equation showing the sum of x and y as follows (Note: We could have used the other equation instead):
x + y = 20
15 + y = 20
15 - 15 + y = 20 - 15
0 + y = 5
y = 5
CHECK:
In order for x = 15 and y = 5 to be the solution to our original system of two linear equations in two unknowns, x and y, this pair of numbers must satisfy BOTH equations as follows:
x + y = 20 x - y = 10
15 + 5 = 20 15 - 5 = 10
20 = 20 10 = 10
Therefore, x = 15 and y = 5 is indeed the solution to our original system of two linear equations in two unknowns, x and y, and the product of the two numbers x = 15 and y = 5 is:
xy = 15(5)
xy = 75
