Question 125846
You can start by writing the equation the expresses the total cost for the phone service: {{{C = F+0.05x}}} Where: C = total cost, F = basic fee($15) and x = the number of minutes at $0.05 per minute.
Making the appropriate substitutions, we get:
{{{71 = 15+0.05x}}} Solve for x by subtracting 15 from both sides.
{{{56 = 0.05x}}} Now divide both sides by 0.05
{{{56/0.05 = x}}} or...
{{{x = 1120}}}minutes.
Check:
{{{C = F+0.05x}}} Substitute F = $15 and x = 1120 mins.
{{{C = 15 + 0.05(1120)}}}
{{{C = 15 + 56}}}
{{{C = 71}}}