Describe the possible values of a ​

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

Harry owes the bank money. to repay his debt, he paid $150 back to the bank each month. after 10 months, his remaining debt was $6900. what was the original amount of harry's debt? how long did it take harry to pay back his entire debt?