Question

The student should answer 10 questions out of 13 on condition that he should answer 4 questions at least from first 5 questions . How many ways can he answer?

Thanks in advance ​

Answer 1

Answer: answer is 196

Step-by-step explanation: If the student answers 4 questions from the first five questions he can choose 6 questions from the remaining 8 questions. Therefore number of combinations will be

5C4×8C6=140

If the student answers 5 questions from the first five questions he can choose 5 questions from the remaining 8 questions. Which will be

5C5×8C5=56

Therefore total number of choices= 140+56=196