SSC CPO SI and ASI Model Paper 9

(4) Sum of money becomes 4 timesof itself in 12 years, therefore, itincreases by 300% in 12 years.
In order to become 7 times of itselfit has to increase by 600%.
Since the sum is increased by300% in 12 years, it will beincreased by 600% in 24 years atsimple interest.
∴Sum of money will become 7times in 24 years.