Answer:
Step-by-step explanation:
Take the coordinates(0,0)(2, -2)(6, -4)(4, -6) and cut each number in half. Then move each point left 3 and up 2.
The z-score for 5 minutes is found from:


Reference to a normal distribution table shows that the cumulative probability for a z-score of 1.667 is around 0.9522.
Therefore the probability that a conversation lasts for longer than 5 minutes is:
1 - 0.9522 = 0.048 to 3 d.p.
Let the speed of the current be y and the speed of Micah's sailing speed be x. Then 4.48/(x + y) = 0.32
4.48/(x - y) = 0.56
0.32x + 0.32y = 4.48 . . . (1)
0.56x - 0.56y = 4.48 . . . (2)
(1) x 7 => 2.24x + 2.24y = 31.36 . . . (3)
(2) x 4 => 2.24x - 2.24y = 17.92 . . . (4)
(3) - (4) => 4.48y = 13.44
y = 3
From (1), 0.32x + 0.32(3) = 4.48
0.32x = 4.48 - 0.96 = 3.52
x = 3.52/0.32 = 11
Therefore, the speed of the current is 3 miles per hour. Answer is 3 miles per hour