JEE Mains · Maths · STD 11 - 6. permutation and combination
The number of natural numbers, between 212 and 999 , such that the sum of their digits is 15 , is
- A 60
- B 61
- C 64
- D 62
Answer & Solution
Correct Answer
(C) 64
Step-by-step Solution
Detailed explanation
Let the number be \(\begin{aligned} & 2 a b, a+b=13 \\ & \Rightarrow a, b \in\{0,9\} \\ & \Rightarrow 6 \text { numbers }\{(9,4),(8,5) \ldots(4,9)\} \end{aligned}\) Similarly, for \(3 a b, a+b=12 \Rightarrow 7\) numbers For \(4 a b, a+b=11 \Rightarrow\) Numbers For…
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