Question 97183
A boy can do a piece of work in 15 days & his father ca do it in 10 days. How long will it take them to do the work together?
:
Let x = time required to complete the job together
:
Let the completed job = 1
:
{{{x/15}}} + {{{x/10}}} = 1
:
multiply equation by 30, to get rid of the denominator
30*{{{x/15}}} + 30*{{{x/10}}} = 30(1)
:
Cancel out the denominators and you have:
2x + 3x = 30
5x = 30
x = 30/5
x = 6 hrs working together
:
:
Check solution. Substitute 6 for x:
{{{6/15}}} + {{{6/10}}} = 1
{{{2/5}}} + {{{3/5}}} = 1