SOLUTION: A can make a wall in 10 days, B can make in 20 days and C cn make in 30 days. If A is assisted by B and C trun by trun in alternate days respectively. In how many days the wall has

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A can make a wall in 10 days, B can make in 20 days and C cn make in 30 days. If A is assisted by B and C trun by trun in alternate days respectively. In how many days the wall has      Log On


   

Question 761361: A can make a wall in 10 days, B can make in 20 days and C cn make in 30 days. If A is assisted by B and C trun by trun in alternate days respectively. In how many days the wall has been completed?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

Principle 1: Number of walls built is directly proportional to number of builders. (i.e. more builders, more walls built)
Principle 2: Time taken to build walls is inversely proportional to number of builders (i.e. if you have more builders, it will take a lesser time to build the same number of walls)
Principle 3: Number of walls is directly proportional to the time taken. (i.e. if you have more walls to build, it will take longer - if the number of builders is the same)
given that:
A can make a wall in 10 days
A can make 1%2F10 of a wall in 1 day

B can make in 20 days
+B can make 1%2F20 of a wall in 1 day
C can make in 30 days
C can make 1%2F30 of a wall in 1 day
all together
1%2F10%2B1%2F20%2B1%2F30+=1%2Fx rate
11%2F60=1%2Fx
so, solve for x
11%2F60=1%2Fx
11x=1%2A60
x=60%2F11
x=5.5 days or x=5 days and 12 hours