Answer:
The value of X is 3.6 minutes.
Step-by-step explanation:
We assume that the time on hold follows a normal distribution with
[tex]\mu=2.5\\\\ \sigma=0.5[/tex]
To calculate how many minutes the 1.5% of the customers are put on hold, we have to determine the z-value for this probability (P=0.015).
Looking in a z-table, the z value is 2.17:
[tex]P(z>2.17)=0.015[/tex]
This can be translated to our distribution as:
[tex]X=\mu+z*\sigma=2.5+2.17*0.5=2.5+1.085\approx3.6[/tex]
The value of X is 3.6 minutes.