UGC NET Paper 1 GA 20 Nov 2021 Shift 1 Solved Paper

Formula Used:
Gain $=$ Selling price $-$ Cost price
Gain percentage $=\left[\right($ Selling price $-$ Cost price $)∕$ Cost price $]\times 100$
Calculation:
Let the selling price of 1 litre milk be Rs. $\mathit{x}$ then, selling price of 33 litres of milk $=33\mathit{x}$
Also given that,
Gain $=$ Selling price of 11 litres $=11\mathit{x}$
Gain = Selling price of 33 litres of milk - Cost price of 33 litres of milk
$\Rightarrow 11\mathit{x}=33\mathit{x}$ - Cost price of 33 litres of milk
$\Rightarrow$ Cost price of 33 litres of milk $=33\mathit{x}-11\mathit{x}=22\mathit{x}$
Gain percentage $=\left[\right($ Selling price $-$ Cost price $)∕$ Cost price $]\times 100$
Gain percentage $=\left[\left(33\mathit{x}-22\mathit{x}\right)∕22\mathit{x}\right]\times 100$
$\Rightarrow \left(11∕22\right)\times 100=50\%$
$\therefore$ The gain percentage is $50\%$.