A bank charges $11/2\%$ per month on the unpaid balance for purchases made with the credit card. This is equivalent to what effective annual interest rate?

$($a$)1\mathrm{.}5\%$

$($b$)12\%$

$($c$)18\%$

$($d$)19\mathrm{.}5\%$

$($e$)39\%$

An "annuity" is defined as

$($a$)$ Earned interest due at the end of each interest period.

$($b$)$ Cost of producing a product or rendering a service.

$($c$)$ Total annual overhead assigned to a unit of production.

$($d$)$ Amount of interest earned by a unit of principal in a unit of time.

$($e$)$ A series of equal payments occurring at equal periods of time.

An individual wishes to deposit a certain quantity of money now so that at the end of five years he will have $$500.$ With interest at $4\%$ per year, compounded semiannually, how much must he deposit now?

$($a$)$ $$340\mathrm{.}30$

$($b$)400\mathrm{.}00$

$($c$)416\mathrm{.}95$

$($d$)410\mathrm{.}15$

The present worth of an obligation of $$10,000$ due in $10$ years if money is worth $9\%$ is nearest to

$($a$)$ $$10,000$

$($b$)9,000$

$($c$)7,500$

$($d$)6,000$

$($e$)4,500$

$$1000$ is borrowed for one year at an interest rate of $1\%$ per month. If this same sum of money is borrowed for the same period at an interest rate of $12\%$ per annum, the savings in interest charges would be:

$($a$)$ $$0$

$($b$)3$

$($c$)5$

$($d$),7$