A point is selected at random from a line segment of length l, dividing it into two line segments. What is the probability that the longer line segment is at least three times as long as the shorter segment

3/4

Step-by-step explanation:

Let a be the length of the shorter line segment and b be the length of the longer line segment.

Since the length of the line segment is l, we have that the length of the line segment equals length of shorter line segment + length of longer line segment.

So, l = a + b

Since we require that the longer line segment be at least three times longer than the shorter line segment, we have that b = 3a

So, l = a + b

l = a + 3a

l = 4a

The probability that the shorter line segment will be a(or 3 times shorter than b) is P(a) = length of shorter line segment/length of line segment = a/l

Since l = 4a.

a/l = 1/4

So, P(a) = 1/4

The probability that a will be less than 3 times shorter that b is P(a ≤ 1) = P(0) + P(a) = 0 + 1/4 = 1/4

The probability that b will be 3 times or more greater than a is thus P(b ≥ 3) = 1 - P(a ≤ 1) = 1 - 1/4 = 3/4

3

step-by-step explanation: