Answer:
Step-by-step explanation:
Given that a particular detection system has a 0.83 probability of detecting a missile attack.
Also each system is independent of the other to detect missile attack.
a) the probability that a single detection system will detect an attack=
b) the probability that at least one of the systems will detect the attack given two systems= 1-Prob no system detects
=
c) If three systems are installed, the probability that at least one of the systems will detect the attack
= 1- none of the three systems detect attack

d) We find that probability of detecting is more if we increase the system form 1 to 2 and 2 to 3.
Hence for safety and defence purpose multiple detection system is recommended.
Answer:
8
Step-by-step explanation:
2x - 2y = -4
-3x -3y = 0
_____________________
-1x - 5y = -4
Answer:
x= -5
Step-by-step explanation:
-7x + 5(2x - 1) = -20
-7x + 10x - 5 = -20
3x -5 = -20
3x = -15
x = -5
the median of her 20 students is 82.5