How can i double an investment every ten weeks?
If you invest in any assets which yields 7.2% per week, then your investment will double. Rule of 72 states "The rule number (e.g., 72) is divided by the interest percentage per period to obtain the approximate number of periods (usually years) required for doubling."
An investment that doubles in value every 10 weeks is generally a VERY risky investment. Safe investments will not normally have a rate of return of more than 500% a year.