Answer: it is NOT proportional
Step-by-step explanation: it doesn’t stick to 1 number going up if that makes sense, it’s adding 1 each time it goes up but it has to stick to one number going up making this NOT proportional
difference is monthly customer fee= 15-10 = $5
difference in minutely charge = 0.08-0.06 = $0.02
minutes it takes for plans to cost same amount= 5÷0.02 = 250 min