I hope this is in the right spot. I need help with this question for my
daughters homework. The question is-Gina wants to save money, so she can buy a
new bike that costs $200. How much should she deposit into a savings account at
10% annual simple interest in order to have enough money to buy the bike after
two years? 
(use the formula A = p + prt)

Substitute 200 for A, .10 for r, and 2 for t

200 = p + p(.10)(2)

200 = p + .2p

200 = 1.0p + .2p

200 = 1.2p

200/1.2 = 1.2p/1.2

166.66··· = p

or $166.67, rounding up to the nearest penny.

Let's check it to see if that is correct. Checking it:

In one year the $166.67 will draw $16.66 interest (investing institutions
always round interest down to the preceding penny), so you'll then have
$166.67 + $16.66 or $183.33

In the second year the $166.67 will draw another $16.66, so you'll then
have $166.67 + $16.66 + $16.66 or $199.99.

That lacks one penny being enough, so let's add a penny and see if $166.68 will
be enough.

In one year the $166.68 will draw $16.66 interest (again rounding down to the
preceding penny), so you'll then have 
$166.68 + $16.66 or $183.33

In the second year the $166.68 will draw another $16.66, so you'll then
have $166.68 + $16.66 + $16.66 or $200.00.

So the correct answer is $166.68

Edwin
AnlytcPhil@aol.com