To simplify the ratio \( 42g : 35g \), we can express it as a fraction:
\[ \frac{42g}{35g} \]
The \( g \) in the numerator and denominator will cancel out, giving us:
\[ \frac{42}{35} \]
Next, we find the greatest common divisor (GCD) of 42 and 35. The GCD is 7. Now we can simplify the fraction by dividing both the numerator and the denominator by their GCD:
\[ \frac{42 \div 7}{35 \div 7} = \frac{6}{5} \]
Thus, the ratio \( 42g : 35g \) simplified to its simplest form is:
\[ \frac{6}{5} \]
So, the final result is:
\[ 6 : 5 \]