q + d = 80
.25q + .10d = 14.45
q. + d= 80
25q + 10d = 1445
-10q. - 10d = -800
25q + 10d = 1445
15q. = 645
q = 43 quarters
43 + d = 80
d= 37 dimes
The answer is x=7 is the answer
N = 1 corresponds to day 1
n = 2 corresponds to day 2
...etc etc...
n = 21 corresponds to day 21
Plug in n = 21
a_n = 100 + (n-1)*4
a_21 = 100+(21-1)*4 ... replace every n with 21
a_21 = 100 + 20*4
a_21 = 100+80
a_21 = 180
Answer: C) 180 yards
