How many years will it take for a sum of money to double at 10% compounded annually

t=7.27 years

Step-by-step explanation:

Let the money be p and t will be the number of years that will be needed for the money to get double.

ATQ, 2p=p*(1+0.1)^t

2=(1.1)^t

log(2)/log(1.1)=t, t=7.27

the 8 in 8,420 is in the thousands place so it's value is 8 thousand.

the 8 in 6,870 is in the hundreds place so it's value is 8 hundred.

divide 8000 by 800 to find the answer:

8000 / 800 = 10

the 8 in 8,420 is 10 times greater than the 8 in 6,870