57+23 = 80
not rounded it's 80.14
Answer:
4 stations
Step-by-step explanation:
If we need to be at least 98% certain that an enemy plane flying over will be detected by at least one station, we must ensure that there is at most a 2% chance that no radar stations detect the plane.
The probability that a single radar station does not detect the plane is 0.35.
For n radar stations:

Rounding up to the next whole station, at least 4 stations are needed.
For the first one to find the total area you have to first find the area of the triangle 1/2(10x12.5)=62.5 and then the square (13.4x12.5)=167.5 which is 10468.75 totaled
36. If 7/11 did bring one, then 4/11 didn't. 4*9=36
Answer:
2/10, 1 1/4, 13/24, 11/24
Step-by-step explanation:
1. subtract the fractions
2. add the fractions
3. add the fractions
4. add the fractions