14 thoughts on “PnC Examples – Whole Number Solutions: Variants

    • Not as such. I have put some video posts on DI last year (which included several LR as well) and for sequences there are several posts. Functions in general is too amorphous a topic I felt, could not think of anything I could do to add value, honestly!


  1. sir in the second last question where a+b+c+d = 20,Since question is asking for even natural no so i took 2,4,6,8 and now the case become distinct no with distinct objects my answer is 4*3*2*1 = 24 ? Please explain where i am wrong

    • You are answering a totally different question – “number of 4 digit numbers with distinct digits such digits are even natural numbers”. Here, we want even numbers and not even digits, and numbers could repeat as well. The numbers could even be 12 or 14 (for example 12 + 2 + 4 + 2 = 20 or 14 + 2 + 2 + 2 = 20)


  2. Hello Sir,

    In the last post, can’t we consider odd numbers to be expressed as 2*a-1 in general? This gives a different answer all together.

    • If you do so, you will have to change your a, b, c, d to natural and not whole numbers (as when a is 0, 2a – 1 will be negative!). The answer will still be the same consequently…


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