Yes. The two groups have the same ratio of students with a solo to total students.
How to solve ratio?
Choir students = 25
Choir students that have solo = 5
Ratio of Choir students to Choir students that have solo = 25 : 5
= 5 : 1
Orchestra students = 20
Orchestra students that have solo = 4
Ratio of Orchestra students to Orchestra students that have solo = 20 : 4
= 5 : 1
Therefore, the both groups have equal ratio.