math
posted by TUHITUHI .
a merchant buys 2 quantities of rice at Rs60 and Rs40 per kg respectively .He pays a total of Rs 1000.On the other hand he paid a flat rate of Rs 500 per kg.He would have paid 10% more.How many kg of each type of rice did he buy?

Let x = rice at Rs60, and y = rice at Rs40. Assuming you have a typo, and meant Rs50/kg, we have
60x + 40y = 1000
50(x+y) = 1050
x=8, y=13