A man sold a radio at 10% gain.if he had bought it at 20% less and sol

1.	A man sold a radio at 10% gain.if he had bought it at 20% less and sold it for rs.10 more he would have gained 40% find the cp of radio.
Answer» Answer: The COST price of radio is Rs.500. Step-by-step explanation: GIVEN : A man SOLD a radio at 10% gain. If he had bought it at 20% less and sold it for Rs.10 more he would have gained 40%. To find : The cost price of radio ? Solution : Let x be the cost price of the goods. A man sold a radio at 10% gain. The SELLING price of goods is $SP=\frac{100+P\%}{100}\times CP$ $SP=\frac{100+10}{100}\times x$ $SP=\frac{110}{100}\times x$ $SP=1.1x$ He had bought it at 20% less. $CP=x-20\%\times x$ $CP=x-0.2x$ $CP=0.8x$ Sold it for Rs.10 more. SP=1.1x+10 The profit percentage formula is given by, $P\%=\frac{SP-CP}{CP}\times 100$ $40=\frac{1.1x+10-0.8x}{0.8x}\times 100$ $0.4=\frac{0.3x+10}{0.8x}$ $0.4\times 0.8x=0.3x+10$ $0.32x=0.3x+10$ $0.32x-0.3x=10$ $0.02x=10$ $x=\frac{10}{0.02}$ $x=500$ Therefore, The cost price of radio is Rs.500.