The population of a town increases at a rate of 10% for every year. If the present population is 12100, find the population two years ago.

11000 9800 10000 10120

10000

Formulae of net effect: x + y + \(\frac{xy }{100 }\) 10 + 10 + \(\frac{100 }{100 }\) = 21% According to question,  Population at present (after increase of 10% every year) = 12100 Population 2 years ago = \(\frac{12100 }{121 }\) x 100 = 10000