Question

26. A and B together can complete a work in 8 days. B alone can complete that work in 12 days. B alone worked for four days. After that how long will A alone take to complete the work? (1) 15 days (2) 18 days (3) 16 days (4) 20 days

11th - 12th Class

Maths

Solution

117

4.0 (1 ratings)

26. (3) One day's work of ( A ) and ( B=frac{1}{8} ) and one day's work of ( B=frac{1}{12} ) One day's work of ( A ) alone ( =frac{1}{8}-frac{1}{12} ) [ =frac{3-2}{24}=frac{1}{24} ] Hence, ( A ) will complete the work in 24 days by working alone Work remaining after working by [ B=1-frac{4}{12}=1-frac{1}{3}=frac{2}{3} ] ( because ) Time taken by ( A ) to do a work ( =24 ) days Thus time taken by ( A ) to ( d o frac{2}{3} r d ) of a work [ =frac{2}{3} times 24=16 text { days } ]