What is the ratio of the number of candidates failing the exam from City D to that of those failing the exam from City A?

$$\eqalign{ & \text{No. of candidates failing from city D} \cr & = \frac{3}{4}\times2.27\times100000 \cr & = \frac{3}{4}\times\frac{227}{100}\times100000 \cr & = 227\times750 \cr & \text{No. of candidates failing from city A} \cr & = \frac{3}{10}\times1.25\times100000 \cr & = \frac{3}{10}\times\frac{125}{100}\times100000 \cr & = 300\times125 \cr & \therefore \text{Required ratio} \cr & = \frac{227\times750}{300\times125} \cr & = \frac{227}{50} \cr & = 227:50 \cr} $$