Cisco Exam 2

A. 100 people took the test, with a total of 5 questions, 80, 72, 84, 88, and 56 for questions 1st, 2, 3, 4, and 5 respectively, if you pass at least three questions, how many people should pass?

B. There are 10 people who want to depart from City A to City B. They only have one (two seats, including the driver) car.

It is known that a and B are 1000 kilometers apart, drive at a speed of 100 kilometers/hour, and walk at a speed of 5 kilometers/hour.

Q: How long does it take for 10 people to reach City B?

 My answer: 1: 62 people 2: 92.16 hours
Process of the first question: in order to make the number of passing students as small as possible, each person can answer as many questions as possible.
Correct 5 questions: 56 people, the remaining correct questions are: 24; 16; 28; 32; 0
Correct 4 questions: 16 people, the remaining correct questions are: 8; 0; 12; 16; 0
Correct 3 questions: 8 people, the remaining correct questions are: 0; 0; 4; 8; 0
A total of 56 + 16 + 8 = 80 people, and 20 others
The 20 people first made the following assignment: 4 people answered question 3, 4 people answered question 3, 4 people answered question 4th 12 people all wrong
Obviously, this allocation is a waste of opportunities that may fail, because only the correct answer to the fourth question and all the wrong answers can be converted into the correct answer to the second question.
Let's take out four people who only answer 4th questions and four people who make all the big mistakes to take up the correct questions.
So no one answered the three questions.
Currently, we can use four people who have the correct answer and eight people who have all the wrong answers. Then, we can make a total of four people who have the correct answer.
4/2 + 8 = 10 people who have correct and four questions have changed to two.
Therefore, the number of people who pass the test is 56 + 16-10 = 62, which is the minimum number of people who pass the test.

Up to 100-88 = 12 answers to 0
88-84 = 4
84-80 = 4
Correct 3: 100-12-4-4 = 80

Set the total time for the car to open forward to X, and the total time for the car to open backward to y.

10 people traveled (including by car) 10*1000 kilometers

Eight people are walking in X time, two people are taking a bus, nine people are walking in Y time, and one person is driving back.

The car eventually arrived at location B from location.

So

(1) (8*5 + 100*2) * x + (9*5-100*1) * Y = 10000

(2) 100 * (x-y) = 1000

Total time t = x + y = 92.16 hours