Bryan spends T=15x
320 divided by 15 is and average of $21 per week
        
             
        
        
        
Answer:
A = $18,326.00
(assuming simple interest)
Step-by-step explanation:
Assuming simple interest, the following formula applies:
final amount = (principal amount) x [1  + (annual rate)(time elapsed) ]
or
A = P (1 + rt)
in our case, 
P = $7,700
r = 5.75% = 0.0575
t = 24 years
hence, 
A = 7700 [ 1 + (0.0575)(24)]
A = 7700 ( 1 + 1.38)
A = 7700 x 2.38
A = $18,326.00   
 
        
             
        
        
        
So the original price is "x".
the discounted price by 10% is P(x) = 0.9x.
the price minus a $150 coupon is C(x) = x - 150.
so, if you go to the store, the item is discounted by 10%, so you're really only getting out of your pocket 90% of that, or 0.9x, but!!! wait a minute!! you have a $150 coupon, and you can use that for the purchase, so you're really only getting out of  your pocket 0.9x - 150, namely the discounted by 10% and then the saving from the coupon.
C(   P(x)   ) = P(x) - 150
C(   P(x)   ) = 0.9x - 150