it takes an apprentice twice as long as the experienced plumber to replace the pipes. if it takes them13 hr when they work together,how long it would take alone

Question

if takes them 13 hr when they work together, how long would it take the apprentice alone?

Answer 1

Here's a simple equation you could use in solving work problems:

 

1/t1 + 1/t2 = 1/td

 

t1 = the time it takes for one person to do the job alone

t2 = the time it takes for the other person to do the job

td = the time it takes to do the job if the two people working together

 

Now, it is given that an apprentice takes twice as long to do the job as the experienced, and also it is given that they could do the job in 13 hrs working together. 

 

Let t1 = the time it takes the experienced plumber to do the job working alone

and t2 = 2*t1 = the time it takes for the apprentice to do the job working alone

td = 13 hrs

 

Now the equation is:

 

1/t1 + 1/(2t1) = 1/13

 

Now, you just need to solve for t1 to get the time it takes for each plumber to do the same job working alone.