Ex.6. A, B and C can complete a wor...
Question
Fullscreen

Ex.6. A, B and C can complete a work in 10, 12 and 15 days respectively. A left the work 5 days before the work was completed and B left 2 days after A had left. Number of days required to complete the whole work is : (1) 8 (3) 7 (2) 6 (4) 6

11th - 12th Class
Maths
Solution
147
Rating
4.0 (1 ratings)
Fullscreen
sol. (3) Let the whole work be completed in ( x ) days A's 1 day's work ( =frac{1}{10} ) B's 1 day's work ( =frac{1}{12} ) C's 1 day's work ( =frac{1}{15} ) According to the question, A's ( (x-5) ) days' work ( + ) B's ( (x-3) ) days' work ( + ) C's ( x ) days' work ( =1 ) ( Rightarrow frac{x-5}{10}+frac{x-3}{12}+frac{x}{15}=1 ) ( Rightarrow frac{6(x-5)+5(x-3)+4 x}{60}=1 ) ( Rightarrow 6 x-30+5 x-15+4 x=60 ) ( Rightarrow 15 x-45=60 Rightarrow 15 x=60+45=105 ) ( Rightarrow x=frac{105}{15}=7 ) days
Quick and Stepwise Solutions Just click and Send Download App OVER 20 LAKH QUESTIONS ANSWERED Download App for Free