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:
I’m coming back to this hold on a sec brotha and be patient
Step-by-step explanation:
Answer:
Marta's rope is 94"
Step-by-step explanation:
D = dilberts rope length
M = marta's rope length
Marta's jump rope is 10" shorter than four times the length of Dilbert's rope
M = 4D-10
both their ropes laid together end to end and measured 120" long
M+D = 120
Substitute 4D-10 for M in the second equation
4D-10 + D = 120
Combine like terms
5D-10=120
Add 10 to each side
5D-10+10 =120+10
5D =130
Divide by 5
5D/5 = 130/5
D =26
Now we need to find M
M+D = 120
M +26 = 120
Subtract 26 from each side
M = 120-26
M = 94