As the number of phones produced increases, will the working rate ever get to 100%? Explain.

Answer:

Although the percentage might eventually round to 100%, it is not possible to have 100% of the phones working. This is because the model began when only 3 out of 10 phones were working, so there are 7 phones that were not working. In other words, the numerator and denominator of the expression are never the same, so the expression is never equal to 1 or 100%.