Answer:
Step-by-step explanation:
The insurance period must be chosen so that the probability of a microchip failure within that period is 4%. Reference to a standard normal distribution table shows that the z-score for a cumulative probability of 4% is -1.75.
Let the insurance period be X months:
-1.75 = (X - 93)/3.8
-6.65 = X - 93
X = 83.35 months.
The answer is 83.35 months.
You start by distributing: 8s-4=7s+12
Combine like terms: 8s-7s=12+4
Solve and get your answer: s=16
Yes you can write a ratio in more than one way
