Answered

Makakuha ng mabilis at pangkomunidad na mga sagot sa IDNStudy.com. Magtanong ng anumang bagay at makatanggap ng agarang tugon mula sa aming dedikadong komunidad ng mga eksperto.

it takes mary 3 hours more to do a job than its takes jane.If they work together, they can finish the same job in two hours.How long would its takes mary to finish the job alone?

Sagot :

Mlcparra16idn
We let the time that Jane takes to finish the job be x, so for Mary it is x+3.
This makes the rates of Jane and Mary be 1/x and 1/(x+3) respectively.
1/[1/x + 1/(x+3)] = 2
1 = 2/x + 2/(x+3)
1 = (4x+6)/(x²+3x)
x²+3x = 4x+6
x²-x-6 = 0

Method 1: Guess and Check
We look for two number with a product of 6 and an absolute difference of 1
6 - 1 = 5  X
3 - 2 = 1  √
So: (x-3)(x+2)=0
Therefore x is either 3 or -2 but we cannot have a negative time so we only consider 3. Therefore Mary's time is 6 hours. It takes her 6 hours to do it alone.

Method 2: Quadratic Formula
x = 1 ± √(1+24) = 1 ± 5 = -2 or 3
              2             2
Again, we cannot have a negative value. So Jane's time is 3 hours and Mary's is 6 hours. So the answer is 6 hours.
it will takes Mary to finish the job alone in 6 hours


Salamat sa iyong pakikilahok. Huwag kalimutang magtanong at magbahagi ng iyong kaalaman. Ang iyong ambag ay napakahalaga sa aming komunidad. Bawat tanong ay may sagot sa IDNStudy.com. Salamat sa pagpili sa amin at sa muling pagkikita.