Supraja and Kausalya can complete a work in 30 days and 20 days, respectively. If Supraja starts the work and they work on alternate days, in how many days will 75% of the work be completed?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 18.
Given:
Supraja and Kausalya can complete a work in 30 days and 20 days, respectively.
Calculations:
Total work (LCM of 30, 20) = 60 units
The efficiency of Supraja = 60/30 = 2
The efficiency of Kausalya = 60/20 = 3
If Supraja starts the work and they work on alternate days,
In 2 days, (2 + 3 = 5) work will be completed
75% of the total work = 3/4 × 60 = 45 units
⇒ Required number of days = (45/5) × 2 = 18 days