Answer:
It will take them approximately 51.43 minutes to complete the project together
Step-by-step explanation:
This is what is called a "shared job" problem.
The best way to work on them is to start by finding the "portion" of the job done by each of the people in the unit of time.
So, for example, Sarah completes the project in 90 minutes, so in the unit of time (that is 1 minute) she completed 1/90 of the total project
Betty completes the project in 120 minutes, so in the unit of time (1 minute) she completes 1/120 of the total project.
We don't know how long it would take for them to complete the project when working together, so we call that time "x" (our unknown).
Now, when they work together completing the entire job in x minutes, in the unit of time they would have done 1/x of the total project.
In the unite of time, the fraction of the job done together (1/x) should equal the fraction of the job done by Sarah (1/90) plus the fraction of the job done by Betty. This in mathematical form becomes:
So it will take them approximately 51.43 minutes to complete the project together.
Answer:
f=3/5x+2/5c
Step-by-step explanation:
Answer:
$13.00
Step-by-step explanation:
Let f represent the price per foot of pasture fence, and p represent the price per foot of picket fence. The two purchases can be written in equation form as ...
2000f + 450p = 12850
700f +300p = 6350
Using Cramer's rule, we can find the value of the picket fence as ...
p = (12850·700 -6350·2000)/(450·700 -300·2000) = -3705000/-285000
p = 13
The cost per foot of picket fence is $13.00.
_____
<em>Cramer's Rule and Vedic math</em>
The above equation for p is a summary of the math you would be doing if you were to solve the equations by eliminating f. Cramer formulates it in terms of determinants of the coefficients in the equations. Practitioners of Vedic math formulate it in terms of X-pattern combinations of the coefficients in much the same way as finding a determinant. For the equations ...
The solutions are ...
∆ = bd -ea
x = (bf -ec)/∆
y = (cd -fa)/∆ . . . . . this is the equation we used above
__
If you do a rigorous comparison of this formula with that of Cramer's rule, you find the signs of numerator and denominator are reversed. That has no net effect on the solution, but it makes the X pattern of products easier to remember for practitioners of Vedic math.
