Ex.2. A and B can together fini a B...
Question

# Ex.2. A and B can together fini a B can together finish a work in 30 days. They worked at it for 20 days and then B left. The remaining work was done by A alone in more days.A alone can finish the work in (1) 60 days (2) 54 days (3) 48 days (4) 50 days SSC CGL (Tler-I) 2014

11th - 12th Class
Maths
Solution
123
4.0 (1 ratings)
Sol. (1) ( (A+B) ) together do the work in 30 days. ( therefore(A+B)^{prime} s 1 ) day's work ( =frac{1}{30} ) ( therefore(A+B)^{prime} s 20 ) day's work ( =frac{20}{30}=frac{2}{3} ) Remaining work ( =1-frac{2}{3}=frac{1}{3} ) Time taken by A in doing ( frac{1}{3} ) work ( =20 ) days ( therefore ) Time taken in doing 1 work ( =20 times 3=60 ) days