Estimate the solution to the following system of equations by graphing. -4x+5y=8 6x - y=11 /2,-7/2) b.( 1/2,3/2) c.(5/2,7/2) /3,8/3)

a) 0.5447

b) 0.0228

c) 0.4325

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean and standard deviation , the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Normal distribution with a mean of 9.6 minutes and a standard deviation of 2.3 minutes.

This means that

a. between 5 and 10 min

This is the p-value of Z when X = 10 subtracted by the p-value of Z when X = 5. So

X = 10

has a p-value of 0.5675

X = 5

has a p-value of 0.0228

0.5675 - 0.0228 = 0.5447 probability that a randomly received emergency call is between 5 and 10 minutes.

b. less than 5 min

p-value of Z when X = 5, which from item a), is 0.0228, so 0.0228 probability that a randomly received emergency call is of less than 5 minutes.

c. more than 10 min

1 subtracted by the p-value of Z when X = 10, which, from item a), is of 0.5675.

1 - 0.5675 = 0.4325

0.4325 probability that a randomly received emergency call is of more than 10 minutes.