3%
Answer:
Selling price with VAT {15%} = Rs 41400
S.P +15% of S.P =Rs 41400
S.P(1+15%)=Rs 41400
S.P=Rs 41400/1.15
Selling price without VAT =Rs 36000
Again
Discount = 10%
M.P =S.P+ Discount % of M.P
M.P-Discount% of M.P= S.P
M.P(1-Discount%)=Rs 36000
M.P(1-10%)=Rs 36000
M.P=Rs 36000/0.9
Marked Price = Rs 40,000
again
Discount =Discount % of M.P
=10% of 40000
=Rs 4,000
Again
Profit=20%
For 20% profit
Cost price = (S.P*100)/(100+profit%)
=(36000*100)/(100+20)
= Rs 30000
For 24% profit
selling price = (100+profit%)*C.P/100
=(100+24)*30000/100
=Rs 37200
Again
Discount = 40000–37200 = Rs2800
Discount % = discount/M.P*100%
=2,800/40,000* 100 = 7%
Finally
Discount percent to be reduced =10%–7%= 3%