So if we have an 80 solution we will need to use 080

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: pent ö æ Work Rate öæ Time Spent ö ç ÷ç ÷+ç ÷ç ÷ =1 è of Mary øè Working ø è of John øè Working ø This time we know that the time spent working together is 3.5 hours. We now need to find the work rates for each person. We’ll start with Mary. 1 Job = ( Work Rate of Mary ) ´ ( 5 ) Þ Work Rate of Mary = 1 5 Now we’ll find the work rate of John. Notice however, that since we don’t know how long it will take him to do the job by himself we aren’t going to be able to get a single number for this. That is not a problem as we’ll see in a second. 1 Job = ( Work Rate of John ) ´ ( t ) Þ Work Rate of John = 1 t Notice that we’ve managed to get the work rate of John in terms of the time it would take him to do the job himself. This means that once we solve the equation above we’ll have the answer that we want. So, let’s plug into the work equation and solve for the time it would take John to do the job by himself. 1 1 ( 3.5) + ( 3.5 ) = 1 5 t 3.5t + ( 3.5)( 5 ) = 5t Multiplying both sides by 5t 17.5 = 1.5t 17.5 =t...
View Full Document

Ask a homework question - tutors are online