Answer:
The total number of feet in all the boards is 90 and 5/6 feet
Step-by-step explanation:
First, it is necessary to transform the mixed number into a fraction. This can be made following the next rule:
[tex]a\frac{b}{c} = \frac{(a*c) + b}{c}[/tex]
So, the number 8 and three fourth feet is equal to:
[tex]8\frac{3}{4} = \frac{(8*4) + 3}{4} = \frac{35}{3}[/tex]
That means that we two boards that are 35/3 feet. So, multiplying 2 by 35/3 we get the total feets for the first type of board. That is:
[tex]2*\frac{35}{3} = \frac{2*35}{3} =\frac{70}{3}[/tex]
At the same way, we can calculate the total number of feet for the second and third type of board as:
[tex]13\frac{5}{8} = \frac{(13*8) + 5}{8} = \frac{109}{8}[/tex]
[tex]4*\frac{109}{8} = \frac{4*109}{8} =\frac{109}{2}[/tex]
[tex]6\frac{1}{2} = \frac{(6*2) + 1}{2} = \frac{13}{2}[/tex]
[tex]2*\frac{13}{2} = \frac{2*13}{2} =13[/tex]
Finally, to find the total number of feet in all the boards, we need to sum the total number of feet for every type as:
[tex]\frac{70}{3} +\frac{109}{2} +\frac{13}{1} =\frac{545}{6}[/tex]
Converting this number to a mixed number we get:
[tex]\frac{545}{6} =90\frac{5}{6}[/tex]
Because, when we divide 545 by 6, we get 90 as a quotient, 5 is the remainder and 6 is the divisor.