Answer:
5/7 ≈ 71.4%
Step-by-step explanation:
There are 19 students total. 4 of them do not play an instrument or a sport. Which means there are 15 students who play either an instrument and/or a sport.
Let's say:
x is the number of students who only play instruments
y is the number of students who play both instruments and sports
z is the number of students who only play sports.
We can use the information to write three equations:
x + y = 7
y + z = 13
x + y + z = 15
Solve the system of equations with either substitution or elimination. Using elimination, add the first two equations:
x + 2y + z = 20
Subtract the third equation:
y = 5
Therefore, x = 2 and z = 8.
So the percent of students who play an instrument who also play a sport is:
y / (x + y)
5 / (2 + 5)
5/7
≈ 71.4%
