a$)2\mathrm{.}7\%$

b$)9\mathrm{.}0\%$

c$)70\mathrm{.}0\%$

d$)91\mathrm{.}0\%$

e$)97\mathrm{.}3\%$

$20.$ A single ambulance is generally available $70\%$ of the time. If two ambulances are stationed in a service area, what is reliability of ambulance service? In other words, what is the probability that an ambulance is available when you call?

a$)2\mathrm{.}7\%$

b$)9\mathrm{.}0\%$

c$)70\mathrm{.}0\%$

d$)91\mathrm{.}0\%$

e$)97\mathrm{.}3\%$