Discounted price before sales tax = 75/100 x (40 + 24 + 18 x 3) = 3/4 x (64 + 54) = 3/4 x 118 = $88.5
Total price inclusive of sales tax = 107/100 x 88.5 = $94.69
2, No solution
3, Infinite many solutions
4, (0,-3)
i hope i was able to help!! so sorry if i made a mistake
It is given in the question that B is in between C and D.
Therefore

Substituting the given values of CB,BD and CD, we will get

Combining like terms, we will get

Now we need to move 4 to the right side by adding 4 to both sides, that is

For this one I would add the measurements for the 3 shins and subtract it from 1.2.
0.125 + .09 + .75 = .965
Then...
1.20 - .965= .235
So...
The fourth board has the width of .235 cm.
Answer:
That's correct but, is this your question? I am confused. If you edit it, I can try to answer your question! :)