Micah invested $3450 in an account paying simple interest. At the end of 6 years, the value of his account was $3967.50. What was the interest rate?

86.25

Step-by-step explanation:

First you have to subract 3450 from 3967.50 so 3867.50-3450=517.5 that gives the money gained over the 6 years.Now you divide 517.5 into 6 years so you can find out what was gained each individual year 517.5 divided by 6 equals 86.25

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