Question

Ex. 1. A and B together can do a work gether can do a work in 10 days. B and together can do the same work in 6 days. and C together can do the work in 12 days. Then A. B and C together can do the work in (1) 28 days (2) 14 days (3) 5 days (4) 8 days

11th - 12th Class

Maths

Solution

4.0 (1 ratings)

Sol. (3) ( (A+B) ) 's 1 day's work ( =frac{1}{10} ) (1) ( (B+C)^{prime} s 1 ) day's work ( =frac{1}{6} ) (11) ( (C+A) ) 's 1 day's work ( =frac{1}{12} ) (111) Adding all three eqn. (i), (ii) and (ii1) ( 2(A+B+C) ) 's 1 day's work ( =frac{1}{10}+frac{1}{6}+frac{1}{12}=frac{6+10+5}{60} ) ( =frac{21}{60}=frac{7}{20} ) ( therefore(A+B+C)^{prime} s 1 ) day's work ( =frac{7}{40} ) ( therefore ) All three together will complete the work in ( frac{40}{7}=5 frac{5}{7} ) days