Answer:
just three units no other numbers?
Step-by-step explanation:
It is given the probability that a dancer like ballet is 0.35
So, P(B) = 0.35
It is given the probability that a dancer like tap is 0.45
So, P(T)= 0.45
The probability that he likes both ballet and tap is 0.30
So, 
the probability that the dancer likes ballet if we know she likes tap. This is the case of conditional probability.
So, 

= 0.666
= 0.67
Therefore, the probability that the dancer likes ballet if we know she likes tap is 0.67.
Option 3 is the correct answer.
Answer:
you simplify the fractions then you cross multiply
Step-by-step explanation:
1/2 * 4/2 you multiply 1 and 4 and you get 4/4 which is equal to 1
The most important part of this question is understanding the words of the problem. The trick lies in the words of the problem. Once the web of words is simplified, the problem becomes very easy. The main thing is converting the words into numbers.
Let us assume the unknown number = x
Then from the question we get
(x/4) = (x/5) + 1
(x/4) - (x/5) = 1
(5x - 4x)/20 = 1
x/20 = 1
x = 20
So the unknown number is 20