A wall in Marcus's bedroom is [tex]$8 \frac{2}{5}$[/tex] feet high and [tex]$16 \frac{2}{3}$[/tex] feet long. If he paints [tex]\frac{1}{2}[/tex] of the wall blue, how many square feet will be blue?

A. [tex][tex]$64 \frac{2}{15}$[/tex][/tex]
B. 70
C. 140
D. [tex]$128 \frac{2}{15}$[/tex]



Answer :

To solve the problem of determining how many square feet of Marcus's wall will be painted blue, we need to go through a few steps systematically:

1. Determine the wall's height and length in mixed numbers and then convert them to improper fractions or decimals for ease of calculation.

- The height of the wall is [tex]\(8 \frac{2}{5}\)[/tex] feet. This can be converted to a decimal as follows:
[tex]\[ 8 \frac{2}{5} = 8 + \frac{2}{5} = 8 + 0.4 = 8.4 \text{ feet} \][/tex]

- The length of the wall is [tex]\(16 \frac{2}{3}\)[/tex] feet. This can be converted to a decimal as follows:
[tex]\[ 16 \frac{2}{3} = 16 + \frac{2}{3} = 16 + 0.6667 = 16.6667 \text{ feet} \][/tex]

2. Calculate the total area of the wall by multiplying the height by the length.

Using the decimal values obtained:
[tex]\[ \text{Total area} = \text{height} \times \text{length} = 8.4 \times 16.6667 \][/tex]

Performing the multiplication:
[tex]\[ 8.4 \times 16.6667 = 140.00000000000003 \text{ square feet} \approx 140 \text{ square feet} \][/tex]

3. Determine the portion of the wall that will be painted blue.

Marcus paints [tex]\(\frac{1}{2}\)[/tex] of the wall blue. Therefore, we need to find [tex]\(\frac{1}{2}\)[/tex] of the total area:
[tex]\[ \text{Blue area} = \frac{1}{2} \times \text{Total area} = \frac{1}{2} \times 140 \][/tex]

Simplifying:
[tex]\[ \text{Blue area} = 70.00000000000001 \approx 70 \text{ square feet} \][/tex]

So, the number of square feet of the wall that will be painted blue is [tex]\( \boxed{70} \)[/tex].