Problema Solution
the cost of a telephone call is 5 pesos for the first three minutes and an additional of 2 pesos for each additional minute or fractional part thereof.
a. find the mathematical model expressing the cost of a telephone call, lasting not more than 15 minutes, as a function of the duration of the call. (hint:greatest integer function)
b. sketch the graph of the function
c. determine the cost of a call lasting 0.5 min., 3 min., and 5 minutes.
Answer provided by our tutors
a.
x = the number of minutes
y = the cost
y = 5, for 0<=x<=3
y = 5 + [x - 3]*2, for 3<=x<=15
where [x] is the greatest integer function.
b.
at the moment we don't have the option to draw graphs.
c.
for x = 0.5 min the cost is y = 5 pesos.
for x = 3 min the cost is y = 5 pesos.
for x = 5 min the cost is y = 5 + [5 - 3]*2 = 5 + 4 = 9 pesos.