i didn t understand what does it asking for :(
Plan B costs 68/mo Plan C costs 92/mo or 24/ mo more... If she saves 45 minutes and thinks it is worth it, then her 45minutes is = to 24 dollars 45mins=24 then One Hour = 24/(45/60) = $32/hr is what she thiks her time is worth.
Plan B is $68 per month
Plan C is $68 + $24 per month 68+24=$92
So if it her work is of greater value than $24 per 45 minutes then plan C will be more economical.
$24 per 45 minutes
$8 per 15 minutes
$32 for 1 hour
So she would have to value her work at more than $32 per hour.