Question

i)How many factors of 210 have? ii)How many factors of 210 have which are divisible by 3?

Answer 1

$$\begin{gathered} \mathrm{The}\mathrm{factors}\mathrm{of}210\mathrm{are}: \\ 1,2,3,5,6,7,10,14,15,21,30,35,42,70,105\mathrm{and}210 \\ \mathrm{So},\mathrm{there}\mathrm{are}16\mathrm{factors}\mathrm{of}210. \\ \mathrm{The}\mathrm{factors}\mathrm{of}210\mathrm{that}\mathrm{are}\mathrm{divisible}\mathrm{by}3: \\ 3,6,15,21,30,42,105\mathrm{and}210 \\ \mathrm{So},\mathrm{there}\mathrm{are}8\mathrm{factors}\mathrm{of}210\mathrm{that}\mathrm{are}\mathrm{divisible}\mathrm{by}3. \end{gathered}$$