logical inference

Question 1: The father is 73 years old and the son is 37 years old.

Solution: From "the age of the father is the age of the son", it can be concluded that the age is within 10- 100, otherwise the son will be older than the father. From "The father's age will be twice that of his son next year", we can get 1: The father's age this year is odd, excluding even. 2. The digits after excluding the father's age in this sentence are 1 or 3, excluding 5, 7 and 9 (if the father's age is X5, X7 and X9, then the son's age is 5X, 7X and 9X times 2, and the father's age exceeds 100, and the remaining 3 and 1 can also be excluded.

Question 2: For three melons.

Solution: Let * * have x melons, then X-(X/2+ 1/2)= 1, and the solvable X=3.

The third question: 5 yuan/kg of tea is 10.5 kg.

Solution: Let 5 yuan/Jin of tea be X Jin, then 3 yuan/Jin of tea is 40-X Jin. Title: * * * 40 kg, 6 yuan/kg 1/3 should get 80 yuan. He said that the profit is 33 yuan, so he can get his capital of 47, and he should strive to achieve x/3 * 5+(40-x).

Question 4: Take it first, lose, and then win.

Solution, this problem is a common multiple solution of 1, 2,4 (I can't make it clear here, let me teach you a way to try. )

No matter how many stones he takes first, the value you take and the value he takes add up as long as it is a multiple of 3 (if he takes one first and you take two, it adds up to 3, if he takes two first, you take one, if he takes four first and you take two, it adds up to 6, which is a multiple of 3. ) Until 100, as long as you follow the rules.

Question 5: The answer is the root number K and the lock is open (I can't type the root number).

If the number n is set to open, then N= root number k (or the square of k =N), of course, n takes an integer (for example, K=8, N=2 times root number, then n takes an integer of 2, that is, two locks are opened) or simply, it is within the range of k value, 1, 2, 3, 4, 5.

That is, 1, 4, 9, 16, 25, no matter how many times the state is switched back and forth. ........................................................................................................................