<p>how to you even set this equation up?</p>
<p>Machine A spends 2500 minutes to do a job. how much time does it take for machine B to do the same job, if when they work together it takes them both 50 minutes to do four jobs?</p>
<p>thanks to all that help</p>
<p>ok using the equation (a*b)/(a+b) to solve for overall time... then u get 50=(2500b)/(2500+b)</p>
<p>then you would multiply both sides... 125000+50ba=2500b... therefore 2450b=125000 b=51.02... i hope i did that right, i didn't have a calculator</p>
<p>There's some trick to it. The question is probably not that difficult. According to cujoe's figuring, the answer would actually be 51.020408163265306122448979591837 .</p>
<p>ya... use the equation axb/a+b... that's assumed that you know it... the rate comparison thingy</p>
<p>ive never used that formula .. ive always been taught</p>
<p>(indiv rate 1)(combined time) + (individual rate 2)(combined time) = # of jobs</p>
<p>is that similar to axb/a+b?</p>
<p>you guys have to take into consideration that it takes them 50 minutes for 4 jobs, not just one. in that case b=12.56</p>
<p>wait, so gxing, i think thats the answer .. but how do u set up the problem? lol sorry, im not good in math</p>
<p>50 = (axb)/(a+b)
50 = (2500b)/(2500+b)
b=51.02
divide b by four since its asking for four jobs
b/4 = 12.56</p>
<p>oh man i didn't even see 4... sorry guys!</p>
<p>Here's an alternative approach that does not require use of the rate formula. </p>
<p>Since m/c A takes 2500 minutes to do a job fully, it does (50/2500) = 0.02 jobs in 50 minutes. That means m/c B did the remaining (4-0.02) or 3.98 jobs in the same 50 minutes, so B takes ( 50/3.98) or 12.56 minutes/job.</p>
<p>I see that you posted your problem in another thread so I'll just copy and paste what I said on the other thread you started:</p>
<p>I know there's an equation you can use, but since you've been looking at it forever I'm gonna infer math isn't your forte so I'll solve it for you using the basic: (rate)x(time)=Jobs</p>
<p>so assume A= rate of machine a (in units of Jobs/minute) and B=rate of machine b (in units of Jobs/ minute)</p>
<p>Using rate x time = jobs:
(2500 minutes) x A = 1 Job & (50)A+(50)B = 4 jobs
Solving for the equation on the left, A= 0.0004 Jobs/minute
Plug that A into the A in the equation on the right and solve for B, and you get B= 0.0796 (Job/minute)</p>
<p>Now you want the time it takes B to do 1 job so you set up the rate x time = jobs equation using the values you have for B and solve for time:
(0.0796 Job/minute) x (time) = 1 Job
time= 1/0.0796= 12.56 minutes</p>