To get the reciprocal of a fraction, just turn it upside down.
A fraction has a numerator, top number, and a denominator, bottom number. To get the reciprocal of a fraction, just swap over the numerator and denominator.
If whole numbers, to get the reciprocal of whole number, just divide the whole number by 1 to make it into a fraction, then get the reciprocal of that fraction.
You will first add all the students the mentioned which gives you 13 then since they ask what is the probability it the teacher would pick girls. You know there's 10 girls and 3 boys so it would be 10/13.
