Kantabai bought 1 1/2 kg tea and 5 kg sugar from a shop. She paid Rs 50 as return fare for rickshaw. Total expense was Rs 700. Then she realised that by ordering online the goods can be bought with free home delivery at the same price. So next ...

Answer: Tea ₹ 300 per kg, sugar ₹ 40 per kg

Let tea cost ₹ \(x\) per kg and sugar ₹ \(y\) per kg.

First purchase: \(\frac{3}{2}x + 5y + 50 = 700\), so \(\frac{3}{2}x + 5y = 650\); multiply by 2: \(3x + 10y = 1300\) ... (I)

Online order: \(2x + 7y = 880\) ... (II)

(I)×2 − (II)×3: \(20y - 21y = 2600 - 2640\), so \(-y = -40\) and \(y = 40\).

From (II): \(2x = 880 - 280 = 600\), \(x = 300\).

Check (I): \(3(300) + 10(40) = 900 + 400 = 1300\), which is true.