Respuesta :
The number of years it would take Becky to double the amount invested is 10 years.
The rule of 70 is a rule of thumb that is used to know the number of years it would take an investment to double at the interest rate. The formula entails dividing 70 by the interest rate.
Rule of 70 = 70 / interest rate
70 / 7 = 10 years
To learn more, please check: brainly.com/question/2262294
Answer:
- About 14.3 years
Step-by-step explanation:
The function for this case would be:
- f(x) = 7x, where f(x) is the average return of %, x - is the number of years
If we need the money to double, the return rate should be 100%:
- 7x = 100
- x = 100/7
- x = 14.3 years