Answer:
Answer
Given equation is:
x
2
−9x+20=0
⇒x
−5x−4x+20=0
⇒(x−4)(x−5)=0
⇒x=4andx=5
3+5+7 = 15 total marbles
3 are red
so she has a 3/15 reduces to 1/5 probability of picking a red one