Two typists undertake to do a job. The second typist begin working one

Let the 1st Typist (A) take x hours and the second typist (B) take y hours.

Work done in 1 hour by A = \(\frac{1}{x}\) and work done in 1 hour by B = \(\frac{1}{y}\)

Now after 3 hours, A has worked for 3 hours and B has worked for 2 hours (starts 1 hour later)

The fraction of work completed by A in 3 hours = \(\frac{3}{x}\) and by B in 2 hours = \(\frac{2}{y}\)


The amount of work completed = \(1 - \frac{9}{20} = \frac{11}{20}\)

So, \(\frac{3}{x} + \frac{2}{y} = \frac{11}{20}\)


At this point, we can use the options to get our answer


Option A: \(\frac{3}{12} + \frac{2}{8} = \frac{1}{4} + \frac{1}{4} = \frac{1}{2}\)


Option B: \(\frac{3}{8} + \frac{2}{5.6} = \frac{3}{8} + \frac{5}{14} = \frac{41}{56}\)


Option C: \(\frac{3}{10} + \frac{2}{8} = \frac{3}{10} + \frac{1}{4} = \frac{11}{20}\)


Option C

Arun Kumar