Answer:
It will take the first person 12 days and the second person x+12 or 20 days
Step-by-step explanation:
The equation for time to do a job is
1/A + 1/B = 1/C
where A is the time for person A to do the job alone
B is the time for person B to do the job alone
and C is the time for A and B to do the job together
Person A does it in x days and Person B does it in x+8 days and together they do it in 7.5 days
Substituting in
1/ (x) + 1/ (x+8) = 1/ 7.5
Multiply by (x)(x+8)(7.5) to clear the fractions
(x)(x+8)(7.5)(1/ (x) + 1/ (x+8)) = (1/ 7.5)(x)(x+8)(7.5)
Distribute
(x)(x+8)(7.5)(1/ (x)) +(x)(x+8)(7.5)( 1/ (x+8)) = (1/ 7.5)(x)(x+8)(7.5)
Cancel
(x+8)(7.5) + 7.5x = (x)(x+8)
Distribute
7.5x +60 +7.5x = x^2 +8x
Combine like terms
15x +60 = x^2 +8x
Subtract 15x from each side
15x-15x +60 = x^2 +8x-15x
60 = x^2 -7x
Subtract 60 from each side
60-60 = x^2 -7x - 60
0 = x^2 -7x - 60
Factor
0 = (x-12) *(x+5)
Using the zero product property
x-12=0 x+5=0
x=12 x=-5
Since the number of days cannot be zero
It will take the first person 12 days and the second person x+12 or 20 days
Answer: its just 6 x 6
Step-by-step explanation:
0 = 1
except if your doing 0 to the power of 0
Answer:
the answer for this question is X=-1/3
<h3>
Answer: 53,560 dollars</h3>
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Explanation:
Having the salary increase by 3% means we can use the multiplier 1.03
Think of it like 100% + 3% = 1 + 0.03 = 1.03
The new salary is 52,000*1.03 = 53,560 dollars
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The slightly longer way to do this is to first figure out how much 3% of 52,000 is
3% of 52,000 = 0.03*52,000 = 1560
Ricardo earns $1560 more dollars on top of the salary of $52,000
So overall his new salary is $1,560 + $52,000 = $53,560
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Personally, I prefer the first method because it's quicker and it allows for multiple percentage increases to chain together. It also could be used to chain in percentage decreases as well.
The answer is A. I hope I helped
