CPhill

I guess this is supposed to be

(x-3.9)/2.2=1.2-x      multiply both sides by 2.2

x - 3.9 = 2.2(1.2 - x)

x - 3.9 = 2.64 - 2.2x         add 2.2x, 3.9 to both sides

x + 2.2x = 2.64 + 3.9

3.2x = 6.54    divide both sides by 3.2

x = 2.04375

Good job, Alan and Melody !!!

I understood your method, Alan......but, am I misreading this?? You say "r" at the "time of interest" = 1m ???  I thought it would be 2/3m based on similar triangles.....

3x^2 = 7(x-3)    simplify

3x^2 = 7x - 21        rearranging gives us

3x^2 - 7x + 21 = 0     this can't be factored, so using the quadratic formula and the on-site solver, we have non-real solutions

$${\mathtt{3}}{\mathtt{\,\times\,}}{{\mathtt{x}}}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{21}} = {\mathtt{0}} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}{\frac{\left({\sqrt{{\mathtt{203}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,-\,}}{\mathtt{7}}\right)}{{\mathtt{6}}}}\\
{\mathtt{x}} = {\frac{\left({\sqrt{{\mathtt{203}}}}{\mathtt{\,\times\,}}{i}{\mathtt{\,\small\textbf+\,}}{\mathtt{7}}\right)}{{\mathtt{6}}}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{x}} = {\mathtt{\,-\,}}\left({\mathtt{\,-\,}}{\frac{{\mathtt{7}}}{{\mathtt{6}}}}{\mathtt{\,\small\textbf+\,}}{\mathtt{2.374\: \!634\: \!474\: \!796\: \!494\: \!3}}{i}\right)\\
{\mathtt{x}} = {\frac{{\mathtt{7}}}{{\mathtt{6}}}}{\mathtt{\,\small\textbf+\,}}{\mathtt{2.374\: \!634\: \!474\: \!796\: \!494\: \!3}}{i}\\
\end{array} \right\}$$

If we have

(10 - 14)    and  (10 - 24),  then

-4 >  -14

If we have

10^-14  and 10^-24     ...then....

10^-14  > 10^-24

So, in either case, the first thing is greater than the second !!!

A = 2000(1 + .025/1)^(1*10)

8/18 + 4 9/18

Adding the fractions, we have 8/18 + 9/18 = 17/18

And adding the "4" to this gives us   4 + 17/18

About 365.2425 days, on the average......

I've examined this electrical circuit with a fine tooth comb.... (actually..a large magnifier).....after careful consideration, it appears that the lights will fail on Monday......thus making Tuesday's exam trivial.......

Those chimps aren't monkeying around.......and they'd better not be.....

By my calculations, that tank holds pi/3*(200cm)²*(600cm) ≈ 25,132,741 cm³ of water

Which means that, if Melody's calculations are accurate......that the whole tank will be filled in about  (25,132,741 / 27, 936, 268) min ≈ 54 seconds

Thus, taking into account the "Primate Float Factor" and "Imperial Minims," means that the chimps will be "washed" out of the tank after a "Total Recreation Time" of less than one minute.....!!!!!

Someone is NOT going to be a happy camper........