65x^2 + 212x - 133
you have to use the quadratic formula
x=( -b +/- √b²-4ac) / 2a
a is 65
b is 212
c is 133
because the first value is squared you will have 2 answers
x= 7/13
x= - 19/5
Answer:
23 1/4
Step-by-step explanation:
A) 25% = 25/100 = 0.25
b) 18% = 18/100 = 0.18
c) 40% = 40/100 = 0.40
d) 2% = 2/100 = 0.02
e) 0.15% = 0.15/100 = 0.0015
SOLUTION
The mean is 4min
standard deviation is 1min
the z score is

where

then we have

The probability the call lasted less than 3 min will be
Therefore, the probability that (z < -1 ) is
[tex]\begin{gathered} Pr(z<-1)=Pr(0
Hence, the percentage of the calls that lasted less than 3 min is 16%