A single discount equivalent to three successive discounts of 22\(\frac{2}{9}\)%, 14\(\frac{2}{7}\)% and 6\(\frac{1}{4}\)% is:

37.5%

i)  22\(\frac{2}{9}\)% = \(\frac{2}{9}\), 

ii) 14\(\frac{2}{7}\)% = \(\frac{1}{7}\) ,

iii) 6\(\frac{1}{4}\)% = \(\frac{1}{16}\)

Here, 

       MRP   :     SP

i)      9      :      7

ii)     7      :      6

iii)   16     :     15

-------------------------

      48     :       30       ⇒ 18 (difference)

Therefore, Discount percent = \(\frac{18}{48}\) × 100 = 37.5%