To find out how many pints of paint Henry needs altogether when he uses 9 pints of yellow paint, we first need to determine the ratio of red to yellow paint he originally used.
Originally, Henry used:
- 2 pints of red paint
- 3 pints of yellow paint
The ratio of red to yellow paint is:
- Red:Yellow = 2:3
Now, if Henry decides to use 9 pints of yellow paint, we can find out how much red paint he would need by maintaining the same ratio of 2:3.
Let \( x \) be the amount of red paint needed for 9 pints of yellow paint. According to the ratio:
\[ \frac{x}{9} = \frac{2}{3} \]
To find \( x \), we can cross-multiply:
\[ 3x = 2 \times 9 \]
Calculating the right side:
\[ 3x = 18 \]
Now, divide both sides by 3:
\[ x = \frac{18}{3} = 6 \]
So, Henry will need 6 pints of red paint to maintain the same shade of orange with 9 pints of yellow paint.
Now, we can calculate the total amount of paint needed:
\[ \text{Total paint} = \text{Red paint} + \text{Yellow paint} = 6 \text{ pints} + 9 \text{ pints} = 15 \text{ pints} \]
Thus, the total amount of paint Henry will need altogether is 15 pints.