Firm A operates $10$ hours each day, producing $100$ parts$/$hour$.$ If productivity were increased $20\%,$ how many hours would the plant have to work to produce $100$ parts?

Question $44$ options:

between $2$ and $6$ hours

between $8$ and $9$ hours

between $9$ and $10$ hours

cannot compute

less than $2$ hours

between $6$ and $8$ hours