Question

Fill in the blanks with correct Number from 1,3,5,7,9,11,13,15 only. you can repeat number. ......+....+......= 30

Answer 1

the sum of 3 odd numbers results an odd number. but 30 is  an even number. so it is impossible to get 30 by adding 3 odd numbers. so it is an impossible event.

Answer 2

There can be many answers but the basic idea is using factorial. Factorial is the product of all the numbers from 1 to that number. For example 4! = 1 x 2 x 3 x 4 = 24.
 
So, 3! + 11 + 13  = 30
Similarly you can find many such answers.

Hope that helps !!