Answer:
solved
Step-by-step explanation:
Mean = 12
SD = 2
Answer to part 2) Less than 7 months
P(x < 7)
P(x < 7) = P(z < (7-12)/2) = P(z < -2.5)
This probability can be obtained by referring to the Z table
Thus P(x < 7) = 0.0062
1) Between 7 and 12 months
P(7 < x < 12) = P( x< 12) - P(x < 7)
We have P(x < 12) = 0 ......[because mean = 12]
and P(x < 7) = 0.0062 ...[this we got is part a]
Thus on plugging these values we get
P( 7 < x < 12) = 0.5 - 0.0062 = 0.4938
Thus P(7 < x < 12) = 0.4938
3
If we represent Tobin's speed as x, we can write her opponent's speed as
x-2 (since Tobin is 2 more than them). In addition, since it's in miles per hour, and 45 minutes is 3/4 of an hour, we can say that 3/4ths of her speed in miles per hour is how long the race is, so (3/4)(x-2)=distance of race. In addition, since it only took Tobin 30 minutes, and 30 minutes is half an hour, x/2 (half of her miles per hour) is the length of the race, so (3/4)(x-2)=(1/2)x. Expanding it, we get 3x/4-6/4=x/2. Subtracting x/2 (or 2x/4) from both sides, we get x/4-6/4=0 and by adding 6/4 to both sides we get x/4=6/4. Multiplying 4 to both sides, we get that x=6=Tobin's speed in miles per hour
The answer is 3 because it goes into 39 and 42 and 6 doesn't go into 39
