A merchant had Rs

Total money merchant has = 78, 592 Rs

Cost of one radio set = 1200 Rs

Cost of 40 radio sets = 1200 × 40 = 48000 Rs

So,

Total money spent on radio sets = 48, 000 Rs

Money left with the merchant = 78,592 – 48,000 = 30,592 Rs

Therefore, total money left with her is 30,592 Rs after the purchase.