S is 20% more than T. T is 10% less than U. What is the ratio of S to U ?

27 : 25 23 : 19 25 : 21 29 : 24

27 : 25

20% = $\frac{1}{5}$ 10% = $\frac{1}{10}$  S  :  T  :  U  6  :  5         9  :  10 ____________ 54 : 45 : 50    S  :  U = 54 : 50 = 27 : 25