To find the percentage of the total amount Justin spent on fruit, we can use the formula:
\[ \text{Percentage} = \left( \frac{\text{part}}{\text{total}} \right) \times 100 \]
In this case, the part is the amount spent on fruit, which is $12, and the total amount spent is $60. Plugging these values into the formula gives:
\[ \text{Percentage} = \left( \frac{12}{60} \right) \times 100 \]
Calculating the fraction:
\[ \frac{12}{60} = 0.2 \]
Now, multiply by 100 to convert it to a percentage:
\[ 0.2 \times 100 = 20 \]
Thus, Justin spent 20% of his total amount on fruit.