Answer:
7
Step-by-step explanation:
Let x be the amount of cups he ordered per month.
There are 12 months in a year.
Therefore, 12 times x plus 16 (the amount he has left) must equal to 100. Thus:
[tex]12x+16=100[/tex]
Subtract 16 from both sides:
[tex]12x=84[/tex]
Divide both sides by 12:
[tex]x=7[/tex]
Therefore, Len ordered 7 cups of tea per month.