Multiple choice

Ruhana is thrice as good a painter as Reshma and together they finish a painting in 18 days. How many days will Ruhana alone take to complete the painting?

  1. 9 days

  2. 20 days

  3. 24 days

  4. 54 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ruhana is 3 times as fast as Reshma. Let Reshma's rate be r, then Ruhana's is 3r. Combined rate = 4r. 4r = 1/18, so r = 1/72. Ruhana's rate is 3/72 = 1/24. Ruhana takes 24 days.

AI explanation

Since Ruhana is thrice as good a painter as Reshma, the ratio of their efficiencies is 3 to 1, making their combined efficiency 4 units. Their combined work completes the painting in 18 days, so the total work is 4 multiplied by 18, which equals 72 units. Ruhana's individual efficiency is 3 units per day, so dividing the total work of 72 units by 3 gives 24 days. Ruhana alone takes 24 days to complete the painting.

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