A man buys eggs at $2$ for $Rs.1$ and an equal number at $3$ for $Rs.2$ and sells the whole at $5$ for $Rs.3.$ His gain or loss percent is

The correct option is B $2\frac{6}{7}\%$ gain

Cost price

2 eggs for 1 Rs.

1 eggs for 1/2 Rs.

3 eggs for 2 Rs.

1 eggs for 2/3 RS.

Total C.P = 1/2 + 2/3 = 7/6

selling price

5 eggs for 3 Rs.

1 eggs for 3/5 Rs.

2 eggs for 2.3/5 Rs.

Gain = Total S.P - Total C.P

$=2.\frac{3}{5}-7/6$

= 1/30 .

% $Gain=\frac{Gain}{C.P}\times 100$

$=\frac{1/30}{\left(7/6\right)}\times 100=2\frac{6}{7}$ % gain.