The seller sold a total of 40 kg of rice bags,

Solution

ATQ, Let, the quantity of Basmati rice bag and Brown rice bag sold be 'a' kg and 'b' kg, respectively. Total cost price of 40 kg Rice bags sold = (3816/1.2) = Rs.3,810 So, the per kg cost price of rice bag sold = (3810/40) = Rs.79.5 ATQ, [(72 × a + 84 × b) /(a + b) ] = 79.5 Or, 72a + 84b = 79.5 × (a + b) Or, 72a + 84b = 79.5a + 79.5b Or, 79.5a - 72a = 84b - 79.5b Or, 7.5a = 4.5b Or, b = (7.5a/4.5) Or, b = (7.5a/4.5) So, b = (5a/3) a + b = 40 Or, a + (5a/3) = 40 Or, 3a + 5a = 40 × 3 Or, 8a = 120 Or, a = (120/8) So, a = 15 So, the quantity of Basmati rice bag sold = a = 15kg