Question

A and b can do a piece of work in 72 days b and c can do it in 120 days a and c can do it in 90 days. then in what time can a do the work alone?

Answer 1

1/A+1/B=1/72
1/B+1/C=1/120 1
1/A+1/C=1/90
add all eqs.
2( 1/ a + 1/ b +1/c )=1/72+1/120+190
1/a +1/b+1/c = divide the above fractions by two
the question asks u to find a therfore using 1st eq ull get a s no of days