Question 1191206
<font color=black size=3>
W = number of weeks
S = total amount of money in the savings account (in dollars)


Shen starts off with $650.
After 1 week, he adds on $30
The balance would be 650+30 which I'll leave unsimplified.


After 2 weeks, he adds on another 30, so,
balance = (650+30)+30 = 650+(30+30) = 650+2*30


Then after 3 weeks, his balance is...
balance = (650+2*30)+30 = 650+(2*30+30) = 650+3*30


At this point you can probably spot the pattern
balance = 650+(number of weeks)*30
which simplifies to
S = 650+W*30
<font color=red>S = 30W+650</font>


Now plug in W = 11 to find how much is in the account after 11 weeks.
S = 30W+650
S = 30*11+650
S = 330+650
S = <font color=red>980</font>


----------------------------------------------------


Answers: 


The equation is <font color=red>S = 30W+650</font>
After 11 weeks, Shen has <font color=red>$980</font> in the account.
</font>