Answer:
Step-by-step explanation:
let the cost of plan A be Y1
and the cost of plan B be Y2
let the number of minutes for both plans be x
let us model the cost of plan A
Y1= 13+0.37x-------1
let us model the cost of plan B
Y2= 28+0.15x------2
when Y1=Y2, we can now solve for x which is in minutes
13+0.37x=28+0.15x
collect like terms
13-28=0.15x-0.37x
-15=-0.22x
divide both sides by -0.22
x=-15/-0.22
x=68.18min