12-0.15×12=$10.2
16-0.15×16=$13.6
20-0.15×20=$17
25-0.15×25=$21.25
Sorry if this didn't help.
<span><span>a8a6)1/7/a2</span> </span>Final result :<span> a12
———
7
</span>Step by step solution :<span>Step 1 :</span> 1
Simplify —
7
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<span>Equation at the end of step 1 :</span><span> 1
((a8) • (a6)) • — ÷ a2
7
</span><span>Step 2 :</span><span> 1
Divide — by a2
7
</span><span>Equation at the end of step 2 :</span><span><span> 1
((a8) • (a6)) • ———
7a2
</span><span> Step 3 :</span></span>Dividing exponential expressions :
<span> 3.1 </span> <span> a14</span> divided by <span>a2 = a(14 - 2) = a12</span>
Final result :<span> a12
———
7
</span><span>
</span>
A)
![\bf \qquad \qquad \textit{Future Value of an ordinary annuity} \\\\ A=pymnt\left[ \cfrac{\left( 1+\frac{r}{n} \right)^{nt}-1}{\frac{r}{n}} \right] \\\\](https://tex.z-dn.net/?f=%5Cbf%20%5Cqquad%20%5Cqquad%20%5Ctextit%7BFuture%20Value%20of%20an%20ordinary%20annuity%7D%0A%5C%5C%5C%5C%0AA%3Dpymnt%5Cleft%5B%20%5Ccfrac%7B%5Cleft%28%201%2B%5Cfrac%7Br%7D%7Bn%7D%20%5Cright%29%5E%7Bnt%7D-1%7D%7B%5Cfrac%7Br%7D%7Bn%7D%7D%20%5Cright%5D%0A%5C%5C%5C%5C)

B)
let's say after 12years, she ended up with a value of say "P"
so.. now she's just sitting on P, making no more deposits to it
just taking whatever the compound 5% interest will give, thus

C)
from A) she made 1,200 every year, for 12 years that's 1200*12, that's how much she put out of pocket, if you got an amount P from A), then the interest is just the difference, or P - (1200*12)
from B), she started with an original amount of P, and ended up with a compounded amount of A after 11years, so the interest is just also the difference, or A - P
add those two folks together, and that's the total interest she got for the 23 years
Since 12 inches is 1 foot, 8 inches must be 96 inches (8 x 12)
the ratio is 3:96.
Oh wait, it can be divided once more by 3.
Therefore, the (final) answer for the scale of the drawing is 1:32