Section 28B(7)(c) in The Rajasthan Administrative Service Rules, 1954
(c)in Services or Groups or Sections thereunder, where there are more than two promotions then first promotion shall be made on the basis of seniority-cum-merit alone and promotions to subsequent higher posts shall be made on the basis of seniority-cum-merit and merit in the proportion of 50:50 except to the highest post.