23. Albert's monthly cell phone bill, y dollars, in terms of the number of minutes of talk time, x, is represented by the equation y = tx + b. In a particular
month, he paid $30 for 100 minutes of talk time. In another month, he paid
$60 for 250 minutes of talk time.
a)
Write the related system of linear equations.
b) Find the values of x and b.
Albert paid $40 in a particular month. For how many minutes of talk
time was he charged that month?