13. Five marks example problems VI

The houses on a street are numbered from \(1\) to \(49\). Senthil’s house is numbered such that the sum of the numbers of the houses prior to Senthil’s house is equal to the sum of the numbers of the houses following Senthil’s house. Find Senthil’s house number?

 

Answer:

 

Senthil’s house number \(=\)