20 boys signed up
# of girls who signed up was 195% of the number of boys who signed up
Find 195% of 20:
1.95 * 20 = 39
So 39 girls signed up.
To find out what percent of girls who signed up for the play attended the auditions, divide 26 to the total number of girls who signed up:
26 / 39 = 0.666666667
Multiply by 100:
0.666666667 * 100 = 66.6666667%
So approximately 66.67% or 66 2/3%