P and Q together can do a job in 6 days. Q and R can finish the same job in 60/7 days. P started the work and worked for 3 days. Q and R continued for 6 days and finish the work. Then, the difference of days in which R and P , independently can complete the job is:

P and Q working together can finish in 6 days. Let P take $p$ days alone and Q take $q$ days alone.

$\frac{1}{p} + \frac{1}{q} = \frac{1}{6}$ ... (Equation 1)

Q and R working together can finish in $\frac{60}{7}$ days. Let R take $r$ days alone.

$\frac{1}{q} + \frac{1}{r} = \frac{7}{60}$ ... (Equation 2)

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P worked for 3 days, then Q and R worked together for 6 days to complete the job:

$3 \times \frac{1}{p} + 6 \times \left(\frac{1}{q} + \frac{1}{r}\right) = 1$

From Equation 2, $\frac{1}{q} + \frac{1}{r} = \frac{7}{60}$:

$\frac{3}{p} + 6 \times \frac{7}{60} = 1$

$\frac{3}{p} + \frac{42}{60} = 1$

$\frac{3}{p} + \frac{7}{10} = 1$

$\frac{3}{p} = 1 - \frac{7}{10}$

$\frac{3}{p} = \frac{3}{10}$

$\frac{1}{p} = \frac{1}{10}$

Therefore, P can complete the job alone in 10 days.

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Using Equation 1:

$\frac{1}{10} + \frac{1}{q} = \frac{1}{6}$

$\frac{1}{q} = \frac{1}{6} - \frac{1}{10}$

$\frac{1}{q} = \frac{5-3}{30}$

$\frac{1}{q} = \frac{2}{30}$

$\frac{1}{q} = \frac{1}{15}$

Therefore, Q can complete the job alone in 15 days.

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Using Equation 2:

$\frac{1}{15} + \frac{1}{r} = \frac{7}{60}$

$\frac{1}{r} = \frac{7}{60} - \frac{1}{15}$

$\frac{1}{r} = \frac{7}{60} - \frac{4}{60}$

$\frac{1}{r} = \frac{3}{60}$

$\frac{1}{r} = \frac{1}{20}$

Therefore, R can complete the job alone in 20 days.

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Difference $= 20 - 10 = 10$ days

Therefore, the difference of days in which R and P independently can complete the job is 10 days.