To find the number of hours \( h \) that Richard needs to work to reach a total of 30 hours for the week, we can set up the equation as follows:
\[ h + 21 \frac{1}{5} = 30 \]
Now, let's convert \( 21 \frac{1}{5} \) to an improper fraction for easier calculation.
To convert \( 21 \frac{1}{5} \):
- Multiply the whole number (21) by the denominator (5): \[ 21 \times 5 = 105 \]
- Add the numerator (1) to this product: \[ 105 + 1 = 106 \]
- Place this sum over the denominator (5): \[ 21 \frac{1}{5} = \frac{106}{5} \]
So the equation now looks like this:
\[ h + \frac{106}{5} = 30 \]
To solve for \( h \), we can isolate it by subtracting \( \frac{106}{5} \) from both sides:
\[ h = 30 - \frac{106}{5} \]
To perform the subtraction, convert 30 to a fraction with a denominator of 5:
\[ 30 = \frac{150}{5} \]
Now the equation is:
\[ h = \frac{150}{5} - \frac{106}{5} \]
Proceed with the subtraction:
\[ h = \frac{150 - 106}{5} = \frac{44}{5} \]
Finally, convert \( \frac{44}{5} \) to a mixed number:
\[ 44 \div 5 = 8 \quad \text{(remainder 4)} \]
This means:
\[ \frac{44}{5} = 8 \frac{4}{5} \]
Thus, Richard needs to work:
\[ h = 8 \frac{4}{5} \text{ hours} \]
Summary:
The complete equation is: \[ h + 21 \frac{1}{5} = 30 \]
And the solution is: \[ h = 8 \frac{4}{5} \text{ hours} \]