The ratio of the incomes of Ram and Shyam is 7 : 17 and that of Shyam and Sohan is 7 : 17. If the income of Ram is Rs. 490, what is the income of Sohan ?

$$\eqalign{ & {\text{Ram}}:{\text{Shyam}} = 7:17 \cr & {\text{Shyam}}:{\text{Sohan}} = 7:17 \cr & = \left( {7 \times \frac{{17}}{7}} \right):\left( {17 \times \frac{{17}}{7}} \right) \cr & = 17:\frac{{289}}{7} \cr & {\text{Ram}}:{\text{Shyam}}:{\text{Sohan}} \cr & = 7:17:\frac{{289}}{7} \cr & = 49:119:289 \cr} $$
Let Sohan's income be Rs. x
Then,
= 49 : 289 :: 490 : x or x = 2890