Answer:
The proportion of callers is put on hold longer than 2.8 minutes is 0.3679
Step-by-step explanation:
μ = 2.8 , λ = 1/2.8 ,
By the exponential distribution:
P(x>k) = exp(-λk)
= exp(-2.8/2.8)
= 0.3679
Therefore, The proportion of callers is put on hold longer than 2.8 minutes is 0.3679