Question

Solve this..
◻ ➕ ◻ ➕ ◻=30
Fill the boxes using
(1, 3, 5, 7, 9, 11, 13, 15)
U can also repeat the numbers.
This question came in UPSC Final Exams held in Dec 2013.
You will be glad to note that only Gaurav Agarwal (IAS Topper) could solve it.

Answer 1

⇒Let me first say you that , when we add odd numbers  ,we do not get a result of even number .

To do this sum , We can solve only through Factorial method ;-

⇒ 15 + 9 + 3 ! = 30 

Here , 3 ! will be equal to -  1 ×2 ×3  .

- Therefore , The answer is - 15 + 9 + 3 ! = 30  

Answer 2

The sum of three odd numbers gives an odd number
So, the sum of 3 given odd numbers doesn’t results 30
So, it is an impossible factor
here we can't use 3! too
because 3! [3×2×1] results a even number 6
so we can’t use it.
If there will be an allowance of factorials, then the answers will be
3! + 15 + 9 =30
3! + 11 + 13 = 30