Explanation:

 Let the number of one-rupee coins, 50-paise coins and 25-paise coins be 2k, 3k and 5k, respectively.
∴ 2k × 1 + 3k × 0.50 + 5k × 0.25 = 114
⇒ 2k + 1.50k + 1.25k = 114
⇒ 4.75k = 114
⇒ k = 24.
50 paise value = 1.5x = 1.5*24 = 36