A pile of cement, 16 bales in the upper layer and 34 bales in the bottom layer, a total of 19 layers

This problem is actually related to the equation of the difference series and the trapezoidal area formula.

Explanation of the difference series: First of all, the number of bags that differ from each other two rows is 2, and we also know the number of bags at the top and bottom, and the number of rows also tells us, so we can use the method of summing the difference series:

Solution: (first term + last term) x number of items 2

16+34）x19/2

50x19/2

380 (pack).

A: There are a total of 380 bales of cement in this pile.

Explanation of the trapezoidal formula: because each layer is two packs apart, so a trapezoid can be formed, then the top can be seen as the upper bottom, the bottom can be seen as the lower bottom, and the number of layers is high, so that it can be found by the trapezoidal area formula:

Solution: (top bottom + bottom bottom) x high 2

16+34）x19/2

50x19/2

380 (pack).

A: There are a total of 380 bales of cement in this pile.

From this, we can also conclude that the trapezoidal area formula is the same principle as the difference series.

...... with a trapezoidal formulaThe number of packs in each layer is exactly the total number of packs = (16+34)x19 2=380

Method 1: Use the trapezoidal formula s = upper bottom (16 packs) + bottom bottom (34 packs) * high (19 packs) total number of packs = (16 + 34) * 19 2 = 380 (packs) Method 2: Sum the difference series.

16+17+18+……33 + 34 = (16 + 34) * 19 2 = 380 (package).

Since it's a pair. Isn't that 2 packs? A pair. Hehe.

You won't know this? It seems that I want to give you an easy way - count it yourself.

s=(a+b)h÷2

198 (pack).

A: There are a total of 189 bales of cement in this pile.

Just follow the usual rules.

Trapezoidal area = (upper bottom + lower bottom) * height 2

s=（a+b）*h\2

189 (pack).

Hello, glad to answer for you It takes some time to type, so please wait.

The calculation process is: 30 + 29 + 28 + 27 + 26 + 25 + 24 = 189 packages.

or (30 + 24) * 7 2 = 189 bags Formula: (first item last item) * number of items 2 cement: powdered hydraulic inorganic cementitious material.

After adding water and stirring, it forms a slurry, which can be hardened in air or water, and can firmly cement sand, stone and other materials together.

Any more questions? You can also pay attention to the answer.,If you have any questions in the future, you can directly consult.,If you're satisfied with my reply.,Please give me a thumbs up after the end of the point Thank you.。

30 + 29 + 28 + 27 + 26 + 25 + 24 = 189 packs.

Or. (30+24)*7 2=189 packets Formula: (first term, last term)*number of items 2

The question in the fourth grade of elementary school is to find the formula for the area of a trapezoid.

189, the sum of the first term plus the last term divided by two, the sum of the difference series.

Summary. If there are a total of x packs, then the first time 1 3x+20 is used, the second time (2 3x-20) 3 5-10, there are 210 packs left, then the three are added: 1 3x+20+(2 3x-20) 3 5-10+210=x, then x=780 packs.

The construction site transported a batch of cement to call Lingming, the first time used all the 1 3 more than 20 bags, the second time used the remaining 3 5 less 10 bags, and the remaining 210 bags were useless.

Suppose there are a total of x packs, then the first time 1 3x+20 was used, the second time (Shinma 2 3x-20) 3 5-10, there are 210 packs of Qiaotanjia left, then the three are added: filial piety 1 3x+20+(2 3x-20) 3 5-10+210=x, then x=780 packs.

Hope it helps you.

Why haven't you sent it yet?

Hair. Didn't you receive it.

No. Wait a minute, I'll send it again.

Suppose there are a total of x packs, then the first time 1 3x+20 was used, the second time (Shinma 2 3x-20) 3 5-10, there are 210 packs of Qiaotanjia left, then the three are added: filial piety 1 3x+20+(2 3x-20) 3 5-10+210=x, then x=780 packs.

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can send a specific process.

No. Kiss this is the specific process, just write this directly when you do math problems.

Wait a minute.

I'll write about it. The process is this ha.

A construction site transported back a batch of cement, the first day to use half of the total number of cement packages more than 50 bags, the second day to use the remaining half of the more than 45 bags, set the total number is x, the first day to use x 2 + 1, at this time also Zheng leaked the remaining x (x 2 + 1), the next day with a search friend to go [x (x 2 + 1)] 3 2, that is, (x 2 1) 3 2 = x 6 7 3, then there is still x (x 2 + 1) (x 6 7 3), should be equal to shouting 16 tons, that is, x (x 2 + 1) (x 6 7 3) = 16, x x 2 1 x 6+7 3=16, x 3=44 3, x=44 tons.

Summary. Dear I'll give you this question, it takes a little time to type, and I will give you the most detailed in 5 minutes. Please be patient

A construction site transported back a batch of cement, the first poor pants used half of the total number of cement packages in one day and 50 more bags, the next day used the remaining half of the virtual attack Jane and 45 more bags, at this time there are 145 bags left, how many bags of water and mud were transported back from this construction site?

Dear I will give you this question, it will take a little time to type, and I will give you the most detailed brother in 5 minutes. Min Pao also asks for your patience and envy for a while

Summary. Hello, please send the original question**Oh<>

2.500 bales of cement were transported to the construction site, 262 bales were used in the first week, and 198 bales were used in the second week1) The first week is Bidi.

Hello, please send the original question**Oh<>

This is the formula for the calculation of the three questions.

Let's set: the first pile is x, and the second pile is 276-x

2/5)x=(276-x) (3/4)

The first pile x=180

The second pile is 276-x=96