A major manufacturer bills $$300$ million worth of cellular equipment per year. The average amount and accounts receivable is $$45$ million. Determine how much time elapses from the time of customer is billed till the time payment is received.

$\mathrm{.}5$ years

$\mathrm{.}15$ years

$\mathrm{.}33$ years

$6\mathrm{.}67$ years