Answer:
Possibility that the students selected are both girls = 31.25%
Explanation:
It is given that
A science class have 5 girls and 3 boys in 7th grade
And 2 girls and 2 boys in the 8th grade
In 7th grade total students = 8
In 8th grade total students = 4
Total possibilities = 8 x 4 = 32
The teacher randomly selects a 7th grade and an 8th grade
The number ways a girl selected from 7th grade = 5c1 = 5
The number ways a girl selected from 8th grade = 2c1 = 2
Total possibilities = 5 x 2 = 10
Probability that the students selected are both girls =10 /32 = 31.25%