Correct Answer - Option 1 : 18 days
Given
Parul takes 6 days more and Karan takes 54 days more to complete the work, than to complete a work together.
Calculation
Let the Parul and Karan together complete a work in x days
Parul = (x + 6) days
Karan = (x + 54) days
1/(x + 6) + 1/(x + 54) = 1/x
⇒ [x + 54 + x + 6]/(x + 6) (x + 54) = 1/x
⇒ (2x + 60)/(x2 + 54x + 6x + 324) = 1/x
⇒ 2x2 + 60x = x2 + 60x + 324
⇒ x2 = 324
⇒ x = 18
∴ Parul and Karan complete the work in 18 days.