### Theory:

Complete the following table

 S.No. C.P. S.P. Profit Loss 1 $$₹$$$$20$$ $$₹$$$$50$$ 2 $$₹$$$$100$$ $$₹$$$$70$$ 3 $$₹$$$$45$$ $$₹$$$$80$$ 4 $$₹$$$$150$$ $$₹$$$$110$$

1. C.P. $$=$$ $$₹$$$$20$$

S.P. $$=$$ $$₹$$$$50$$

S.P. $$>$$ C.P.

Therefore, there is a profit.

$$\text{Profit}$$ $$=$$ $$\text{S.P.}$$ $$-$$ $$\text{C.P.}$$

$$= 50 - 20$$

$$=$$ $$₹$$$$30$$

2. C.P. $$=$$ $$₹$$$$100$$

S.P. $$=$$ $$₹$$$$70$$

C.P. $$>$$ S.P.

Therefore, there is a loss.

$$\text{Loss}$$ $$=$$ $$\text{C.P.}$$ $$-$$ $$\text{S.P.}$$

$$=$$ $$100 - 70$$

$$=$$ $$₹$$$$30$$

3. C.P. $$=$$ $$₹$$$$45$$

S.P. $$=$$ $$₹$$$$80$$

S.P. $$>$$ C.P.

Therefore, there is a profit.

$$\text{Profit}$$ $$=$$ $$\text{S.P.}$$ $$-$$ $$\text{C.P.}$$

$$= 80 - 45$$

$$=$$ $$₹$$$$35$$

4. C.P. $$=$$ $$₹$$$$150$$

S.P. $$=$$ $$₹$$$$110$$

C.P. $$>$$ S.P.

Therefore, there is a loss.

$$\text{Loss}$$ $$=$$ $$\text{C.P.}$$ $$-$$ $$\text{S.P.}$$

$$= 150 - 110$$

$$=$$ $$₹$$$$40$$

Now, the table looks like this:

 S.No. C.P. S.P. Profit Loss 1 $$₹$$$$20$$ $$₹$$$$50$$ $$₹$$$$30$$ Nil 2 $$₹$$$$100$$ $$₹$$$$70$$ Nil $$₹$$$$30$$ 3 $$₹$$$$45$$ $$₹$$$$80$$ $$₹$$$$35$$ Nil 4 $$₹$$$$150$$ $$₹$$$$110$$ Nil $$₹$$$$40$$