In a group of 22 pupils, 4 play the flute only

Question

In a group of 22 pupils, 4 play the flute only.
3 play the piano only.
7 play neither instrument.
A student is selected at random.
What is the probability the student plays both instruments?

Answer 1

probability is super easy - don't overthink it or expect it to be harder...

 

P = 4/22 flute

P = 3/22 piano

P = 7/22 no instruments

P = 0/22 both 

 

P=0 the answer is in the problem.  If you're asked to simplify, then just reduce the fraction if it's reducible, so, for example flute could be reduced to 2/11, or changed to a percentage of 2 divided by 11, which is .18, or 18%