Two people start from home at the same time, how many minutes later the distance between the two people to the school is equal? (solved by equation)

Two people start from home at the same time, how many minutes later the distance between the two people to the school is equal? (solved by equation)

Let's set the distance between two people to school equal after X minutes, 1.2km = 1200m, 0.95km = 950m, 1200-100x = 950-75x, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 25X = 260, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 10

Xiao Ming walks 80 meters every minute and arrives 10 minutes ahead of time. Xiao Li walks 60 meters every minute. How many meters does it take to go to school

First of all, let Xiao Li's time be X minutes
Xiao Ming walks 80 meters every minute and arrives 10 minutes in advance. Xiao Li walks 60 meters every minute and arrives at school just in time
The conclusion is that Xiaoming walks 80 meters per minute, 10 minutes ahead of time and Xiaoli walks 60 meters per minute
Therefore, since the formula distance = velocity x time s = V x T
So, 80 x (X-10) = 60x 80x-80 x 10 = 60x 80x-800 = 60x, the one with X is on the left, and the one without x is on the right
The conclusion is: 80x-60x = 800, 20x = 800, x = 40
So: total distance = Xiaoli's time x effective speed = 40 x 60 = 2400 meters
For reference only, I wish you good luck and hope to help you!

If Xiao Li walks 30 meters per minute, she is 3 minutes late; if Xiao Li walks 40 meters per minute, she is 5 minutes early,
How many meters is the distance between Xiao Li's home and school

The distance between Xiaoli's home and school is x meters
X/30-3=X/40+5
X/30-X/40=3+5
X/120=8
X=960
The distance between Xiaoli's home and school is 960 meters

How to measure the circumference of a dollar coin with a scale

First, measure the diameter of the coin with a scale. In order to accurately clamp the coin between two things, the length of the diameter is between the points on two sides, and the circumference is equal to 3.14 * D. D represents the diameter
It seems that my method is a bit troublesome_ ∩∩∩∩∩∩∩∩∩∩∩∩∩∩∩∩∩

Xiao Ming bought a pen and an exercise book for 2.4 yuan. The price of the exercise book is twice that of the coin. How much is the unit price of the pencil and exercise book?
Solve by equation

Let X be the pencil and 3x be the exercise book
X+3X=2.4
4X=2.4
X=0.6,
The unit price of pencil is: 0.6 yuan / piece, the unit price of exercise book is: 0.6 * 2 = 1.2 yuan / piece

Min bought two pencils and three erasers for a total of 1.8 yuan, while Mi bought four pencils and two erasers for a total of 2 yuan for the same coin eraser. How much is an eraser

2 pencils + 3 erasers = 1.8 yuan, X2 = 4 pencils + 6 erasers = 3.6 yuan, 4 pencils + 2 erasers = 2 yuan, 4 pencils + 2 erasers = 2 yuan

It costs 37 yuan to buy 5 coins, 3 ballpoint pens and 1 pencil, and 39 yuan to buy 3 coins, 6 ballpoint pens and 9 pencils. How much does it cost to buy 1 coin, 1 ballpoint pen and 1 pencil
I can't work out the equation

The answer is: 9 detailed analysis process: equation 1: 5A + 3B + C = 37; equation 2: 3A + 6B + 9C = 39; equation 2 can get equation 3: a + 2B + 3C = 13; equation 3 times 5 can get equation 4: 5A + 10B + 15C = 65; equation 4 minus equation 1 can get equation 5: 7b + 14C = 28, that is: B + 2C = 4

Try to bite the upper end of the pencil with your teeth, tap the lower end of the pencil with your fingers (as shown in the figure), listen to the knock, then open your mouth so that your teeth do not touch the pencil, and keep the position of the pencil unchanged. Your fingers use the same force as before to light the lower end of the pencil. Compare the two knocks______ Sound transmission ability ratio______ Sound transmission______ ．

When you tap a pencil, the sound can be transmitted to the ear through pencil and air, and the pencil has fast transmission speed and good transmission effect, so the first sound transmission effect is better than the second one

Of the following objects with a mass of about 2kg ()
A. Two eggs B. an old hen c. a big sheep D. a desk

The weight of an egg is about 0.05kg-0.1kg, a sheep should be more than tens of kg, and the desk should be more than ten kg, so B

Did you see an eraser on the desk just now

Did you see the eraser on the desk just now?
It refers to the rubber on the table