A meter is sold at a gain of 16%.if it was sold for 20dollars more,there would be gain of 20%.find?

the question is not clear, suggest reformulating.

if the meter was sold with a profit of 16% which meant 20 USD, then the initial cost was X*1.16=x+20 => x = 20/0.16 = 125 USD

If you want to find out what the profit would be at 20%, then it is 25 USD