Answer: 1.25
Step-by-step explanation:
Given: A college-entrance exam is designed so that scores are normally distributed with a mean = 500 and a standard deviation
= 100.
A z-score measures how many standard deviations a given measurement deviates from the mean.
Let Y be a random variable that denotes the scores in the exam.
Formula for z-score =
Z-score =
⇒ Z-score =
⇒Z-score =1.25
Therefore , the required z-score = 1.25
Remove both sets of brackets.
18 - 9x - 8 + 12x > 9 Collect like terms on the left.
12x - 9x + 18 - 8 > 9
3x + 10 > 9 Subtract 10 from both sides.
3x > 9 - 10
3x > - 1 divide by 3
x > -1/3
Notice what the graph is telling you. A blue dotted line is going through x = - 1/3 or - 0.3333
Everything to the right of - 0.333 is colored blue and that means anything to the right if going to be a solution to the inequality. To confirm this for yourself, try zero and 1. Both should give larger than 9 solutions.
