Amita can build a room in the same amount of time that Bina and Sita working together can build. If Amita and Bina together could do it in 25 days and Sita alone in 35 days, then how many days are required for Bina alone to do the same work?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 175 Days.
Time taken by Amita and Bina = 25 days
Time taken by Sita = 35 days
Let the total amount of work to be done LCM(25, 35) be 175 units.
Efficiency of Amita + Bina = = 7 units/day
Efficiency of Sita = = 5 units/day
Now, let the efficiency of Amita be A and efficiency of Bina be B.
⇒ B = 7 - A
Given that, A = B + S
⇒ A = (7 - A) + 5
⇒ 2A = 12
⇒ A = 6 units/day
Now, efficiency of Bina, B = 7 - 6 =m 1 unit/day
Time taken by Bina alone to complete the work = = 175 days
Hence the number of days required by Bina to complete the work is 175 Days,