To find the mass of one tennis ball, we can divide the total mass of the three tennis balls by the number of balls.
The total mass of the 3 balls is given as \(6 \frac{3}{10}\) grams. We can convert this mixed number to an improper fraction:
\[ 6 \frac{3}{10} = \frac{6 \times 10 + 3}{10} = \frac{60 + 3}{10} = \frac{63}{10} \text{ grams} \]
Now, we divide the total mass by 3 to find the mass of one ball:
\[ \text{Mass of one ball} = \frac{\frac{63}{10}}{3} = \frac{63}{10} \times \frac{1}{3} = \frac{63}{30} \]
Now we can simplify \( \frac{63}{30} \):
\[ \frac{63 \div 3}{30 \div 3} = \frac{21}{10} \]
Converting \( \frac{21}{10} \) back to a mixed number:
\[ \frac{21}{10} = 2 \frac{1}{10} \]
Thus, the mass of one tennis ball is \(2 \frac{1}{10}\) grams.
So the answer is:
2 1/10 grams