Given:
CP of 20 bats = Rs. 12000
Let the selling price of 1 bat be Rs.x
Therefore Gain = Rs. 4x
SP of 20 bats equals Rs.20x
Therefore Gain = SP - CP
or, 4x = 20x - 12000
or, 12000 = 20x - 4x
or, 16x = 12000
or, x = 12000/16
or x = 750.
Therefore Selling price of one bat is Rs. 750(Ans)
I hope you understood
Regards