The monkey mother picked 17 peaches and gave them to three baby monkeys, 1 / 2 to Dabao, 1 / 3 to Erbao and 1 / 9 to Sanbao. How many peaches should each baby monkey give?

Dabao: 17x (1 / 2) / (1 / 2 + 1 / 3 + 1 / 9) = 9
Two treasures: 17x (1 / 3) / (1 / 2 + 1 / 3 + 1 / 9) = 6
Sanbao: 17x (1 / 9) / (1 / 2 + 1 / 3 + 1 / 9) = 2

The mother monkey picked back some peaches. The little monkeys ate 1 / 2 of the peaches on the first day and the remaining 1 / 3 on the second day

Total number of peaches × (1 - 1 / 2) × (1 - 1 / 3) = 20
Total number of peaches × 1 / 2 × 2 / 3 = 20
Total number of peaches = 20 × 3 / 2 × 2 = 60

The supermarket promoted sales. Three empty bottles were exchanged for one bottle of drink. Nine people bought six bottles of drink. As a result, everyone drank one bottle. Why

Six people drank six bottles of drinks, that is, there were six empty bottles, changed two bottles of drinks, and three people didn't drink, so they borrowed one bottle of drinks, that is, three bottles of drinks, and then three people drank all three bottles, that is, there were three bottles, and then they exchanged three empty bottles for one bottle of drinks to return the original one, so that everyone drank one bottle

In the supermarket, two pens are 10 yuan, "buy ten get one free" (buy ten get one free) promotion. If you buy one pen for all 44 students in the class, how much do you have to pay at least?

44 (10 + 1) = 44 (11) = 4 (pieces), buy 40 pieces, and give 4 pieces as a gift; (10 △ 2) × 40 = 5 × 40 = 200 (yuan) a: at least 200 yuan

Supermarket promotion activities: Pen 2 yuan, buy 3 get 1 free, the teacher wants to buy 100 for singing competition players as a gift, ask how much it will cost?

(4-1) * 2 * 100 / 4 = 150 yuan

Before the holiday, the school is going to buy 60 "hero" pens priced at 8 yuan to reward the ten star students, and a cultural goods store happens to carry out a profit giving promotion
Store a: give one free for every five bought; store B: give a 15% discount; store C: return 30 yuan in cash when the price is over 200 yuan
Which shop is more suitable to buy?

A: buy 50 pieces, give 10 free, 50x8 = 400 yuan
B: 60x85% = 408 yuan
C: 60x8 = 480480 △ 200 = 2.80480-2x30 = 420
Therefore: shop a is the cheapest

Mr. Chen of the general affairs office of the school went to the supermarket to buy 28 identical pens, which cost 448 yuan. According to this calculation, if Mr. Chen bought another 8 pens, how much would he have to pay before and after? (solve by proportion)

A: a total of 576 yuan will be paid for the front and back

It is stipulated in a shopping mall that every five empty bottles can be exchanged for one bottle of beverage. A person can buy drinks for 28 yuan. How many bottles can he buy at most? (3.5 yuan per bottle)

3.5*8=28
Now it's eight bottles
5 bottles for 1 bottle
Now it's nine bottles
There are four bottles left
Now I'll lend you a bottle
You drink the tenth drink
Give me back the bottle, so you can drink 10 bottles at most

A, B two shopping malls in the "May Day" golden week promotional activities
If the total amount of goods purchased is more than 200 but less than 400, 100 yuan will be paid less; if the total amount of goods purchased is more than 400 but less than 600, 200 yuan will be paid less,
(1) If the customer bought 510 yuan goods in a shopping mall, how much yuan should he pay?
(2) The price of a commodity is x (200 ≤ x ＜ 400) yuan in a and B shopping malls. Which shopping mall do you think costs less? Explain the reason

1) 510-200 = 310 yuan
2) The second is really troublesome. There are several situations
The first type: X-100 < 0.6x
x＜250
So when 200 is less than x is less than 250, choose a
Second: X-100 = 0.6x
x=250
So when x equals 200, both a and B are OK
The third: X-100 > 0.6x
x＞250
So when 250 < x is less than 400, choose B

During the "May 1st" golden week, in order to promote the sales of goods, both stores a and B take preferential measures. Store a will give a 20% discount after the 20% discount, while store B will give a 60% discount at one time. If the goods of the same price are sold, the following conclusion is correct ()
A. A than B discount B. B than a discount C. two stores have the same preferential terms D. can not be compared

If the unit price of goods is x yuan, then the selling price of shop a is x × 0.8 × 0.8 = 0.64x yuan; the selling price of shop B is x × 0.6 = 0.6x yuan, ∵ 0.64x ＞ 0.6x, and shop B is preferential

The monkey mother picked 17 peaches and gave them to three baby monkeys, 1 / 2 to Dabao, 1 / 3 to Erbao and 1 / 9 to Sanbao. How many peaches should each baby monkey give?