A businessman's earnings increase by 25% in one year but decrease by 4% in the next year. Going by this pattern, after 5 years, his total earnings would be 72000. What is his present earning?

40000

25% = \(\frac{1}{4}\)   let original value = 4 , increased value = 5

4% = \(\frac{1}{25}\)  let original value = 25, decreased value = 24

after 5 years amount is = 72000

initial sum is

72000 × \(\frac{4}{5}\) × \(\frac{25}{24}\)×\(\frac{4}{5}\)×\(\frac{25}{24}\)× \(\frac{4}{5}\)  = 40000