Question

In an examination the ratio of the number of suo:essful candidates to unsuccessful candidates is 7:5. Had 30 more appeared and 10 more passed, the ratio of successful candidates to unsuccessful candidates would have been 4:3. Find the number of candidates who appeared in the examination originally. 

Answer 1

Let successful candidates be 7x and unsuccessful candidates be 5x.

Now , `(7"x" + 10)/(5"x" + 20) = 4/3`

⇒  21x + 30 = 20x + 80 

⇒ x = 50

7x = 7 x 50 = 350 

5x = 5x50 = 250

.·. 7x + 5x = 350 + 250 = 600 

Therefore, there were 600 candidates originally.