Ratios don't have to be "per" something, while rates are "per" something.
Ratios compare 2 or more values, as well as rates.
Answer:
- The system of equations is x + y = 85 and 7/20x+2/5y=31
- To eliminate the x-variable from the equations, you can multiply the equation with the fractions by 20 and multiply the other equation by -7.
- B-She used 60 minutes for calling and 25 minutes for data.
Step-by-step explanation:
It is always a good idea to start by defining variables in such a problem. Here, we can let x represent the number of calling minutes, and y represent the number of data minutes. The the total number of minutes used is ...
x + y = 85
The total of charges is the sum of the products of charge per minute and minutes used:
7/20x + 2/5y = 31.00
We can eliminate the x-variable in these equations by multiplying the first by -7 and the second by 20, then adding the result.
-7(x +y) +20(7/20x +2/5y) = -7(85) +20(31)
-7x -7y +7x +8y = -595 +620 . . . . eliminate parentheses
y = 25 . . . . . . . . simplify
Then the value of x is
x = 85 -y = 85 -25
x = 60
Answer:
Step-by-step explanation:
distribute 2 into (4x+2) and -12 into (x-1)
8x+4=4x-12x+12
combine like terms
8x+4=-8x+12
add -8x on both sides
8x+8x+4=12
16x+4=12
subtract 4 on both sides
16x=8
divide both sides by 16
x=1/2
hope this helps
Answer:
n = -45
Step-by-step explanation:
(n-5) /10 = -5
Multiply each side by 10
(n-5) /10 *10= -5*10
n-5 = -50
Add 5 to each side
n-5+5 = -50+5
n = -45
Answer:
Y = 45*p(y) / (1 - p(y)) if I knew what p(y) is, we can find how many yellow marbles there are. p(y) = probability of choosing yellow.
Step-by-step explanation:
Total marbles = 35 + 10 + yellow
If probability of choosing yellow =p(y) = yellow/Total
p(y) = Y/(35 + 10 + Y)
Solve for Y,
p(y)*(35 + 10 + Y) = Y
45*p(y) + p(y)*Y = Y
45*p(y) = Y - p(y)*Y
Y = 45*p(y) / (1 - p(y))
