The voltage in a certain circuit is a random variable with mean 120 and standard

Question

The voltage in a certain circuit is a random variable with mean 120 and standard deviation 5. Sensitive equipment will be damaged if the voltage is not between 112 and 128. What is the probability that the equipment will be damaged?

I believe this requires using Z tables.

I got z = (128-120)/5

z= .32

I looked at Z from left to right and got .6217

So I subtracted by .5(this is at z=0), so .6217-.5 = .1217

Then multiplied by 2 to get .2434

I definitely made an error somewhere, this doesn't make logical sense.

Explanation / Answer

PROBABilty that equipemnt will get damaged=P(X>128)+P(X<112) =1-P(X<128)+P(X<112)

=1-P(Z<(128-120)/5)+P(Z<(112-120)/5) =1-P(Z<1.6)+P(Z<-1.6)=1-0.9452+0.0548=0.1096

please revert

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