2 april's journal entry...i didinot understand the calculation

Dear student,
Answer to the question
Trade discount is to be calculated on the List price and is to be deducted from the List price
                                                                                         Rs          Rs
April 2      List price                                                     6000
             Less: Trade Discount @15%on Rs6000         900
             Purchase price                                                                5100

Out of the entire purchase,40% is paid in cash at the same time -
 Cash purchase ( prompt paymen)t is 40% of Rs 5100 = Rs 2040

 Cash discount is allowed @ 2%. Cash discount is allowed on prompt cash payment
Thus Discount received is 2% on Rs 2040 = Rs 40.80 or Rs 41
Actual Cash payment = Rs 2040 - Rs 41 = Rs 1999

Credit purchase from Sharma Brothers is 60 % of Rs 5100 = Rs 3060

Journal entry
                                                                                                      Dr(Rs)                 Cr(Rs)
April 2       Purchase A/c                                    Dr                     5100
                    To Sharma Brothers A/c                                                                   3060
                     To Cash A/c                                                                                       1999
                     To Discount received A/c                                                                    41
( Being goods purchased from Sharma Brothers for Rs 5100, paid 40% in cash and received 2% cash discount)

Regards