How many ways to read the palindromic word ROTATOR in this design?

Question

The problem is as follows:

The figure from below shows the word $\textrm{ROTATOR}$ arranged in a peculiar way. How many ways can this word be read assuming the equal least distance from one letter to another?.

The alternatives given in my book are as follows:

$\begin{array}{ll} 1.&\textrm{490 ways}\\ 2.&\textrm{480 ways}\\ 3.&\textrm{245 ways}\\ 4.&\textrm{400 ways}\\ \end{array}$

I noticed that the word is palindromic, hence it can be read back and forth, thus this means that I should account for these possibilites.

In order to keep the right track for this purpose I used an auxiliary numbers atop the letters to account for these as shown in the diagram from below.

After doing all of that I reached the conclusion that:

$\textrm{ways}=(74+74+96)\times 2 =488$

But this doesn't appear in any of the alternatives. Did I mess up something or what? Can someone help me here? Please I require a step by step explanation as I feel lost if my method did worked out properly?

Answer 1

Here is a slightly easier argument.
Let's just count how many ways there are to go from an R to an A. The R's on one side give this:

$$R^1 \quad R^1 \quad R^1\\ O^1 \quad O^2 \quad O^2 \quad O^1 \\ T^3 \quad T^4 \quad T^3 \\ A^3 \quad A^7 \quad A^7 \quad A^3$$

Starting at the R's on the other end gives this:

$$A^4 \quad A^7 \quad A^7 \quad A^4 \\ T^1 \quad T^3 \quad T^4 \quad T^3 \quad T^1 \\ O^1 \quad O^2 \quad O^2 \quad O^1 \\ R^1 \quad R^1 \quad R^1$$

Adding those together, there are $7$, $14$, $14$, and $7$ ways to go from any R to each of the central A's. Conversely there are the same number of ways to go from each of those A's back to any R. Combining any R-to-A path with any A-to-R path from the same A we get $7\cdot7+14\cdot14+14\cdot14+7\cdot7 = 490$.

Answer 2

As @Peter hinted in a comment, we have to count for paths going from left to right, right to left as well as left to central $A$ column and back to left and so on.

Notation : $^{m}T^{n}$ indicates $T$ was first reached in $n$ number of ways and later $m$ total number of ways. Read right number first, left number second always.

Left to right paths (unidirectional): $$ R \quad R \quad R\\ O^{1} \quad O^{2} \quad O^{2} \quad O^{1} \\ T^{3} \quad T^{4} \quad T^{3} \\ A^{3} \quad A^{7} \quad A^{7} \quad A^{3} \\ T^{3} \quad T^{10} \quad T^{14} \quad T^{10} \quad T^{3} \\ O^{13} \quad O^{24} \quad O^{24} \quad O^{13} \\ R^{37} \quad R^{48} \quad R^{37} $$

Left + Right $= 2(37+48+37)=2\cdot 122 = 244$

Left to center and back to left : (top to bottom to top) $$ ^{34}R^{0} \quad ^{48}R^{0} \quad ^{34}R^{0}\\ ^{10}O^{\color{red}{1}} \quad ^{24}O^{\color{red}{2}} \quad ^{24}O^{\color{red}{2}} \quad ^{10}O^{\color{red}{1}} \\ ^{10}T^{3} \quad ^{14}T^{4} \quad ^{10}T^{3} \\ A^{3} \quad\quad A^{7} \quad\quad A^{7} \quad\quad A^{3} $$

Left to center, back to left : $34+48+34=116$

Right to center and back to right : (bottom to top to bottom) $$ A^{4} \quad\quad A^{7} \quad\quad A^{7} \quad\quad A^{4} \\ ^{4}T^{1} \quad ^{11}T^{3} \quad ^{14}T^{4} \quad ^{11}T^{3} \quad ^{4}T^{1} \\ ^{15}O^{\color{red}{1}} \quad ^{25}O^{\color{red}{2}} \quad ^{25}O^{\color{red}{2}} \quad ^{15}O^{\color{red}{1}} \\ ^{40}R^{0} \quad ^{50}R^{0} \quad ^{40}R^{0} $$

Right to center, back to right : $40+50+40=130$

Total ways : $244+116+130=490$

Answer 3

Starting from the top A there are $1+2+1+3=7$ routes to an R. So there are $7^2$ ways through that A.

Starting from second A down there are $(1+3+3)\times2=14$ routes to an R. So there are $14^2$ ways through that A.

So the total number of ways is $7^2+7^2+14^2+14^2=490$.