Cost of one radio = ₹ 1200
Cost of 40 radios = 1200 x 40 = ₹ 48,000
Now,
Total money with merchant = ₹ 78,592
Money spent by her = – ₹ 48,000
Money left with her = ₹ 30,592
Therefore, ₹30,592 will remain with her after the purchase.