The cost of this gift is 18 yuan, and the list price is 2 1 yuan.
As a result, the young man took out 100 and bought this gift.
Boss Wang didn't have any change at that time, so he changed 100 yuan from the neighborhood and gave it to the young man 79 yuan.
But later, the neighborhood found that this 100 yuan was counterfeit, and Boss Wang had no choice but to return this 100 yuan to the neighborhood.
The question now is: How much did Boss Wang lose in this transaction?
In this question, most people think the answer is 197 yuan, or 200 yuan. Actually, the answer is 97 yuan. This is a question that 9 people in 10 will be wrong.
Let's turn the question around and think about what neighbors and young people get. It's even clearer ~ ~
Neighborhood changed the change of 100 yuan to the boss and then changed it to 100 yuan with the boss, which means that the neighborhood and the boss have no interest relationship. The boss received young people's 100 yuan counterfeit money and gave young people change from 79 yuan. That is to say, the young people get the gift of 18 yuan +3 yuan's profits and 79 yuan's money, so obviously, the boss loses the gift of 18 yuan +3 yuan's profits and his change for 79 yuan.
The boss lost 79+ 18=97 yuan.
Today, my mother took me to the supermarket to buy things. My mother bought a lot of things. She just wanted to check out, but she remembered that she still didn't buy detergent. So my mother and I went to buy detergent again. We went to the place where detergent was sold and saw two kinds of detergent. The prices and discounts were different. Mom said, "You can calculate for me which one is cost-effective." The first one is 14 yuan 500 ml, and the second one is 16 yuan 500 ml with 80 ml. I calculated that 500÷ 14≈35 (ml) is 35 ml per yuan, 500+80=580 (ml), and 580÷ 16=36.25 (ml) is 36.25 ml per yuan. I picked up the second one and went to check out. My mother surprised me and said I was really smart.
My mother tested my topic: "I saw a topic on a test paper recently." The number of A is three times that of B. If the number of A given by B is six, then the number of A is five times that of B. What are the numbers of A and B? "
I thought about it and said, "I really can't. Can you teach me? " Mom said, "He said that number A is three times that of number B, so let's divide number B into 1 times, number A into three times, number B into number A, and number A is five times that of number B. From this, we can think that if number B is subtracted from number B, number A will be added to number B. Now, number A is three times more than number B, and we can divide number A into as many numbers as number B. I won't say it now. Can you find the number of A? "
"It's too simple. 2 1 times 3 equals 63, the number a is 63 and the number b is 2 1.
One day, I was doing my homework at home. Suddenly, I was stumped by a math problem: A and B were 546 kilometers apart, and two buses started from both places at the same time, facing each other and met for 3 hours. It is known that the speed of car A is three times that of car B. How many kilometers does car A travel per hour? I believe many students will feel headache after reading it, so will I, obviously it is not easy to calculate! Finally, I still use what the teacher taught me in class to enlighten me and solve the problem. Didn't the teacher teach me assumptions? Then I can assume that car B travels one kilometer per hour, car B travels three kilometers, car A travels three times as fast as car B, and car A travels nine kilometers, so they travel 12a kilometers, that is, 12a kilometers = 546 kilometers. You see, with this assumption, it is very simple to solve this problem. With 546 ÷ 12 = 45.5km, the speed of car B is 45.5km, and then with 45.5x3 = 136.5km, the speed of car A is 136.5km. It can be seen that the hypothesis is a small coup to solve mathematical problems.
My mother took me to the vegetable market to buy eggs. Egg price:
Foreign eggs 1 kg 10, 1 0.9 yuan.
Grass eggs 1 kg 6, 1 1.8 yuan.
Mom asked, "Xiaojie, our family only bought half a catty. How can we get the best deal? " I thought to myself: If I buy foreign eggs, I will use 10÷2=5 (pieces) and 5 × 0.9 = 4.5 (yuan). Buy grass eggs, 6÷2=3 (pieces), 3× 1.8 = 5.4 (yuan). Buying foreign eggs should be a good deal. No, later I thought: It costs 5.4-4.5 more to buy grass eggs than foreign eggs = 0.9 yuan. Since grass eggs are more expensive than foreign eggs, how much is a grass egg more expensive than foreign eggs? With 1.8-0.9 = 0.9 yuan, one grass egg equals two foreign eggs. From this point of view, buying grass eggs is more cost-effective than buying foreign eggs.