If two persons, with equal abilities, can do two jobs in two days then 100 persons with equal abilities can do 100 similar jobs in = ?

$$\frac{{{{\text{2}}_{{\text{person}}}} \times {{\text{2}}_{{\text{days}}}}}}{{{{\text{2}}_{{\text{jobs}}}}}} = \frac{{{\text{100}} \times {\text{D}}}}{{{\text{10}}{{\text{0}}_{{\text{jobs}}}}}}$$      (D is number of days required)
$$\eqalign{ & {\text{After solving}} \cr & {\text{D}} = 2{\text{ days}} \cr} $$