100
T-Mobile are Verizon are both offering new monthly plans for students under the age of 18. Verizon's plan costs $20/month, plus $10 for every gigabyte of data used. T-Mobile's plan costs $40/month, plus $6 for every gigabyte of data used.
Write a linear equation for each company relating Y, the total monthly cost, to X, the number of gigabytes of data used.
Y = 20 + 10x (Verizon)
Y = 40 + 6x (T-Mobile)