Description for Correct answer:
Let cost of 1 pencil and 1 clipper be p and c, respectively

Now. according to the question,

\( \Large 21p + 9c = Rs.819 \)

\( \Large 3 \left(7p+3c\right)= Rs.819 \)

\( \Large 7p + 3c = Rs.273 \)

Cost of 7 pencils and 3 clippers = Rs.273.