2 1/2 miles = 1/6 hours
2 1/2 miles * 6 = 1/6 hours * 6
12 1/2 miles = 6/6 hours
12 1/2 miles = 1 hour
12 1/2 miles/hr
<em>Y</em>₁ and <em>Y</em>₂ are independent, so their joint density is

By definition of conditional probability,
P(<em>Y</em>₁ > <em>Y</em>₂ | <em>Y</em>₁ < 2 <em>Y</em>₂) = P((<em>Y</em>₁ > <em>Y</em>₂) and (<em>Y</em>₁ < 2 <em>Y</em>₂)) / P(<em>Y</em>₁ < 2 <em>Y</em>₂)
Use the joint density to compute the component probabilities:
• numerator:






• denominator:

(I leave the details of the second integral to you)
Then you should end up with
P(<em>Y</em>₁ > <em>Y</em>₂ | <em>Y</em>₁ < 2 <em>Y</em>₂) = (1/6) / (2/3) = 1/4
Answer:
here,x=123, is the answer.