Math puzzle: Calculate the age of people sitting at four round tables.
Calculate the age of the people sitting at the four round tables.
Four people are sitting at the table. Their ages add up to 45, 56, 60, 7 1, 82 respectively, and there are two others that don't add up. From this, can you work out their ages?
Answer: Four people are 17, 28, 39 and 43 years old. What is not added is 28+39=67.
Math puzzle: How to distribute the inheritance according to the will?
How to distribute the inheritance according to the will?
A rich man's wife was pregnant with her first child. The rich man's will reads as follows: "If my wife gives birth to a son, my son will inherit 2/3 of the estate, and my wife will inherit 1/3 of the estate; If the wife gives birth to a daughter, the daughter inherits 1/3 and the wife inherits 2/3. " Unfortunately, the rich man died of illness before the baby was born. His wife gave birth to twins. How to follow the rich man's will and divide the inheritance among his wife, son and daughter?
Answer: The son is twice as old as his wife, and the wife is twice as old as her daughter. This is equivalent to the inheritance being divided into 4+2+ 1=7, 4/7 for the son, 2/7 for the wife, and the rest 1/7 for the daughter.
Math puzzle: Calculate whether Lao Wang earned, lost or even?
Calculate whether Lao Wang earned, lost or even?
Old Wang Mai bought two ancient coins and later sold them at the price of each 60 yuan. One of them made 20% and the other lost 20%. Compared with when he bought these two ancient coins, did Lao Wang make a profit, lose money or be flat?
Answer: I lost 5 yuan. If each 60 yuan is sold, the purchase price of the ancient coins with a profit of 20% is: X÷( 1+20%)=60, x=50 yuan, and the purchase price of another ancient coin with a loss of 20% is: y÷( 1-20%)=60 yuan. In this way, the purchase price of two ancient coins is 50+75= 125 yuan, while the selling price is 120 yuan, so Lao Wang lost 5 yuan money in this transaction.
Math problem: How many sons and cows does the farmer have?
How many sons and cows does the farmer have?
A farmer gave his son a herd of cows.
Because the eldest son is 1 cow and 1/7 of the rest of the cattle;
For the second son, the remaining two cows and herds of 1/7,
The third son got 1/7 three cows and the rest of the herd;
For the fourth son, it is 1/7↓ of the four eldest sons and the rest of the herd.
And so on. In this way, he divided the whole herd among his sons. How many sons does he have? How many cows are there?
Answer: to solve this problem by arithmetic (that is, without equations), we must start from the end. The youngest son should get the same number of cows as the son; The remaining 1/7 is not his, because there are no cows after him. Then, a son in front of him got 1 less than his sons, plus the rest of the herd 1/7. In other words, the youngest son gets 6/7 of this remainder. So it can be seen that the number of cows earned by the younger son should be divisible by 6. Try to assume that the youngest son gets 6 cows and see if this assumption holds. The youngest son has six cows, that is, he is the sixth son, and that man has six sons. The fifth son should get 5 cows plus 7 cows 1/7, which is 6 cows. Now the two youngest sons * * * get 6+6= 12 cows. It should be that after the fourth son gets the cows, the rest of the herd is 12+6/7= 14/7 = 6 cows, so the fourth son gets 4+ 14/7=6 cows. Now calculate the remainder of the herd after the third son gets the cow: 6+6+6 is 18, which is 6/7 of this remainder. Therefore, the total remainder should be 18÷7/6=2 1. So the second son is worth 3+2 1/7=6. Similarly, the eldest son and the second son each got six cows. Our hypothesis has been confirmed, and the answer is that * * * has six sons, each son gets six cows, and the herd * * * consists of 36 cows. Are there any other answers? Suppose the number of sons is not 6, but a multiple of 6, 12. However, this assumption will not work. The next multiple of 6, 18, won't do either. You don't have to bother to go any further.
Math puzzle: How many percentage points has the original price increased now?
When a commodity is reduced by 20%, how many percentage points has the original price increased now?
If the price of a commodity is reduced by 20%, how many percentage points should the current selling price be increased to be the original price?
Answer: 25%
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