Starting from the origin of the number axis, an electronic flea jumps one unit to the right for the first time, two units to the left for the second time, three units to the right for the third time, four units to the left for the fourth time What is the distance from the flea to the origin if you jump 100 times according to this rule?

Starting from the origin of the number axis, an electronic flea jumps one unit to the right for the first time, two units to the left for the second time, three units to the right for the third time, four units to the left for the fourth time What is the distance from the flea to the origin if you jump 100 times according to this rule?

0+1-2+3-4+5-6+… +99-100 = - 50, so the distance from 0 is 50 units

The first step is to jump 1 unit to K1 from K0 to the left, the second step is to jump 2 units to K2 from K1 to the right, the third step is to jump 3 units to K3 from K2 to the left, the fourth step is to jump 4 units to K4 from K3 When jumping 100 steps according to the above rule, the number represented by k100 on the number axis is exactly 30, then the number represented by K0 on the initial position of the flea is ()
A. -26B. -20C. -30D. 30

Let the electronic flea fall on a certain point on the number axis K0 = a, and the left is negative and the right is positive +100=30，a+（2-1）+… +(100-99) = 30, a + 50 = 30, a = - 20

1. An electronic flea is at a certain point K0 on the number axis. In the first step, it jumps two units to the left from K0 to K1, and in the second step, it jumps four units to the right from K1
Unit to K2, the third step moves 6 units from K2 to K3 to the left, the fourth step jumps 8 units to K4 to the right After jumping 50 steps according to the above rule, the flea falls at the origin
2. On a parallel Lane beside the railway, a pedestrian and a cyclist start eastward at the same time. The speed of the pedestrian is 3.6 km / h and the speed of the cyclist is 10.8 km / h. a train comes from behind them. It takes 21 seconds to pass the pedestrian and 24 seconds to pass the cyclist. The length of the train is () M

1. 50 steps is even, so the origin is on the right. When n steps (and N is even), the distance from kn to Ko is n steps, so the distance from Ko to the origin is 50. Because Ko is on the left side of the origin, so Ko table (- 50,0) 2

A kind of clothing costs 120 yuan and makes 40%. How much is the price?

If you make 40%, you can use 120 times 40% = 48 yuan

If the price of a garment is 120 yuan and it is sold at 20% off the marked price and still earns 32 yuan, the marked price is 100 yuan______ Yuan

(120 + 32) △ 80%, = 152 △ 0.8, = 190 (yuan); answer: the price is 190 yuan; so the answer is: 190

If a casual dress is sold at 60% off the price, the owner can earn 32 yuan. It is known that the purchase price of the dress is 58 yuan. How much is the original price

The original price is 150 yuan
Let X be the original price,
X*60% - 58 = 32

If the price of a garment is 120 yuan and it is sold at 20% off the marked price and still earns 32 yuan, the marked price is 100 yuan______ Yuan

(120 + 32) △ 80%, = 152 △ 0.8, = 190 (yuan); answer: the price is 190 yuan; so the answer is: 190

A clothing store sells two sets of clothes at the same time, and each set sells 168 yuan. According to the cost calculation, one set makes a profit of 20%, and the other set loses 20%?

Suppose the cost of the profitable suit is X Yuan and the cost of the loss suit is y yuan. From the meaning of the question, we get x (1 + 20%) = 168, y (1-20%) = 168, and the solution is x = 140, y = 210. Answer: the cost of these two suits is 140 yuan / set and 210 yuan / set respectively

A clothing store will sell two pieces of clothing with different prices for 90 yuan, one of which will make a profit of 20%, and the other will lose 20%. In this transaction, the loss or the win

Win
90+（90*20%）=108
90-（90*20）=72
108-72=36
A: the profit is 36 yuan
(100% original, I have done this question, 100% correct)

Today, the clothing store sold a piece of clothing for 120 yuan with a profit margin of 20%. Can you work out the purchase price? (answer with the equation of one yuan per time)

Express delivery day,
Suppose the purchase price is x yuan
X×（1＋20%）＝120
120%X＝120
X＝120÷120%
X＝100