AP EAMCET · Maths · Permutation Combination
A student has to answer 10 out of 13 questions in an examination. The number of ways in which he can answer if he must answer atleast 3 of the first five questions is
- A 376
- B 276
- C 286
- D 386
Answer & Solution
Correct Answer
(B) 276
Step-by-step Solution
Detailed explanation
Total number of ways \[ \begin{aligned} & ={ }^5 C_3{ }^8 C_7+{ }^5 C_4{ }^8 C_6+{ }^5 C_5{ }^8 C_5 \\ & =10 \times 8+5 \times 28+1 \times 56 \\ & =80+140+56=276 \end{aligned} \]
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