Question 207414
ben finishes his work in 8 days. frank works 3 times faster than ben.
james works 5 times faster than ben.
How many days will it take for them to finish the job together?
:
Ben's time = 8 days
Frank's time = {{{8/3}}} days
Jame's time = {{{8/5}}} days
:
Let t = time to finish working together
Let the completed job = 1
:
{{{t/8}}} + {{{t/((8/3))}}} + {{{t/((8/5))}}} = 1
:
Invert the dividing fraction and multiply, results
{{{t/8}}} + {{{3t/8}}} + {{{5t/8)}}} = 1
:
Multiply equation by 8
t + 3t + 5t = 8
:
9t = 8
t = {{{8/9}}} days working together