Two third grade math problems, and two third grade math problems

The first question, set up volleyball and bought x pieces.

Because the number of soccer balls purchased is 3 times the number of volleyballs, you can know that the number of soccer balls is equal to 3x, and according to the fact that there are 18 more soccer balls than volleyballs, you can know that the number of soccer balls is x+18

The two equations are equal and the equation is listed as follows:

3x=x+18

2x=18x=9

That is, there are 9 volleyballs, and the number of soccer balls is 3x, which is 27.

In the second question, the father is three times older than the son after X years.

After x years, the father is (50+x) years old and the son's age is 14+x years.

The columns are as follows. 50+x=3（14+x）

50+x=42+3x

2x=8x=4

After four years, the father will be three times as old as the son.

Football 27 volleyball 9

4 years later. Let the number of volleyballs x, then the number of soccer balls is 3x 3x-x=18, then x=9

After x, 50+x=3(14+x) gives x=4

y=3xy=x+18

x=9 Soccer 27 Volleyball 18

50+x=3*（14+x）

x=4 four years later

Solution: Suppose the father was 5 times older than the son X years ago.

50-x)/(14-x)=5

14*5-5x=50-x

70=50+4x

4x=20x=5 Answer: 5 years ago, the father was 5 times older than the son.

Set volleyball x yuan, then basketball (x 10) yuan, football (x 8) yuan x (x 10) (x 8) 3 36

3x＋18＝108

3x 90x 30 football: 30 8 38 yuan.

If the volleyball is x, then the soccer ball is 3x.

3x-x=18

x=93x=27

So 9 for volleyball and 27 for football.

After n years, the father is 3 times older than the son.

Then 14n=50 3n=

"Red + East = 188 points", "Army-East = 1 point", add these two equations to get the equation "Red Army = 189 points", and then add the three equations of "Army + Li = 184 points" and "Li + Red = 187 points" to get: "Army + Li + Red + Army + Li + Red = 560 points", divide both sides of the equation by 2 at the same time to get the total score of 3 people "Army + Li + Red = 280 points", and then subtract the total score of two of them respectively to get the score of the other person, minus "Army + Li = 184 points", get Red = 96 points;

minus "beauty + red = 187 points", winning army = 93 points;

minus "Red Army = 189 points", Deli = 91 points;

In the end, according to the score of 93 points of the army, and "army-east = 1 point", the score of the east is calculated to be 92 points.

I hope it inspires you and can help you.

(Seen as A, B) Army + Li = 184 1

C, b) Li+ Red = 187 2

C + D) Red + East = 188 3

A-D) Army-East = 1 4

From 3 + 4, we get: A + C = 189

A=189-C5

Bring 5 into 1 to get: C-B = 5 6

From 2+6, we get: 2C = 192 C = 96 so D = 92 A = 93 B = 91

1,1+2+3+4+5+6=(1+6)*3 It was found that the first and last groups were added and the same amount, and they were divided into 3 groups.

2. Look at the picture.

1 I will not say anything.

2 (Army + Li) + (Li + Red) + (Red + East) = 184 + 187 + 188 (Army + East) + 2 (Li + Red) = 184 + 187 + 188 (Army + East) + 2 * 187 = 184 + 187 + 188 (Army + East) = 185

And the condition Army-East = 1 means that the Army has one more point than East.

Army = East + 1 put "Army = East + 1" into the formula "(Army + East) = 185".

Then East + 1 + East = 185

East = 92 points Other launches Army 93 Red 96 Li91

Liz = 91

Jun = 184 - Liz = 184 - 91 = 93

Red = 187 - Lil = 187 - 91 = 96

East = Army - 1 = 93 - 1 = 92

Liz = 91 Army = 184 - Liz = 184 - 91 = 93

Red = 187 - Lil = 187 - 91 = 96

East = Army - 1 = 93 - 1 = 92

Because Li+Red = 187 points, Red + East = 188 points, so East minus Li=188-187=1 point.

Because Jun-Dong = 1 point, East minus Li = 1 point.

So the military minus Li = 2 points.

Because Jun + Li = 184 points.

So army = (184 + 2) 2 = 93 points.

Liz = 93-2 = 91 points.

East = 93-1 = 92 points.

Army + Li = 184 points = 187 points = 188 points = 1 point (Army + Li) - (Li + Red) + (Red + East) - (Army - East) = 184-187 + 188-1 = 184

2 East = 184

East = 92 Red = 188 - East = 188 - 92 = 96

Army = 1 + East = 93

Liz = 184 - Jun = 184 - 93 = 91

188 + 1 = 189 (Red + Army).

184 + 187 + 189 = 560 (Army + Li + Li + Red + Army + Red) 560 divided by 2 = 280 (Army + Li + Red).

Red: 280-184=96

Army: 280-187=93

Leigh: 280-189=91

According to Army-East = 1 point, Army = 93 points, get East = 93-1 = 92 points This is my method, I hope it will help you a little!

Army + Li = 184 points, Red + East = 188 points, that army, Li, Hong, and Dong add up to 372 points, Li + Red = 187 points, that Army + East = 372-187 = 185, Army - East = 1 point, that is to say, the army is one more point than the East, Army + East = 185, Army = (185 + 1) 2 = 93 points, East = 93-1 = 92 points, Red = 188-92 = 96, Li = 184-93 = 91 hope to adopt, I wish your niece's academic performance to improve every day.

=(1+2+3+4+5+6)×1000+(2+3+4+5+6+7)×100+(3+4+5+6+7+8)×10+(4+5+6+7+8+9)

2.Add Jun + Li = 184 Red + East = 188.

Army + Li + Red + East = 184 + 188

Li+ Red = 187

Therefore, the army + east = 184 + 188-187 = 185 because the army has one more point than the east, and the more (185 + 1) 2 = 93 is the score of the army.

Dong's score is 92, Leigh's score is 184-93=91, and Red's score is 187-92=95.

First use (Li + Red) - (Army + Li) = Red - Army = 187-184 = 3, (Red + East) + (Army - East) = Red + Army = 188 + 1 = 189:;

Reuse (Red-Army) + (Red+Army) = Red + Red = 3 + 188 = 192, so Red = 192 2 = 96;

Li=187-96=91;Army=184-91=93;East = 188-96 = 92

Answer: Army = 93 Li=91 Red = 96 East = 92 Army + Li=184 So Li=184 - Army.

So Li+Red=187 becomes 184-Army+Red=187, so Red-Army=3, so Red=3+Army.

So red + east = 188 becomes 3 + army + east = 188 so army + east = 185 so east = 185 - army.

In the end, Army-East = 1 becomes Army-(185-Army) = 1

In this way, find the army = 93 and the rest can be found.

The army is one point bigger than the east, the red is three points larger than the army, the red is four points bigger than the east, east + 4 + east = 188, ok army + li = 183

Red + Liz = 187

That's why Red is a senior in the army.

sorry is East + 5 + East = 188

It's wrong again or 4

Dong-Li = 188-187 = 1

4 people in total: 184 188 = 372

Jundong = 372-187 = 185 = ( 1 ) east = (185-1) 2 = 92

Army = 92 1 = 93

Liz = 184-93 = 91

Red = 187-91 = 96

Count yourself 、、、 children, everyone has experienced such a tragedy

You add up the left part of the four formulas, add up the numbers on the right, and connect them with an equal sign. Appearance: 2 Army + 2 Liz + 2 Red = 560.

Army + Li+ Red = 280. With this formula, subtracting (Jun + Li=184) equals 96, which is red. By analogy, 280-187=93 is the army, and 187-96=91 is the beauty.

93-1=92 is East.

Good... Off-line calculations.

We have an additional question for this, but it's done.

, which means that the east is more than Lili 1, and the army is 1 more than the east, then the army is 2,188 2=94, which is the average of the army and Li, then the army is 94+1=95, Lili is 94-1=93, then the red is 187-93=94, and the east is 188-94=94