Question

Raju and Tom together can do a work in10 days.Tom and appu together can do it in 12 days.appu and raju together can do it in 15 days .in how many days will they finish it if all the three work together

Answer 1

sol: 1 /10 of work done by Raju and appu in one day
1/12 of work done by Tom and appu in one day
1/15 of work done by appu and raju in one day
Now
work done by all three groups in one day =
1/10 +1/12+1/15=450/1800
450/1800 of work done in one day
or
in on day work done 450/1800
in how many days work done =1/450/1800.
=1/1×1800/450
= 1800/450
= 4 days
if they work together they finish in 4 days