If 12 tons of grain are transported from warehouse A to warehouse B, the ratio of grain stored in warehouse A to warehouse B is 9:13. How many tons of grain were stored in warehouse B? I'm in a hurry

If 12 tons of grain are transported from warehouse A to warehouse B, the ratio of grain stored in warehouse A to warehouse B is 9:13. How many tons of grain were stored in warehouse B? I'm in a hurry

Lemon smoothie,
The amount of grain stored in the first granary is 20% more than that in the existing granary, and that in the second granary is 20%
1÷（1＋1＋20%）＝10/22
The proportion of grain stored in warehouse A and warehouse B is 9:13, and the proportion of grain stored in warehouse A and warehouse B is 1:1
13÷（9＋13）＝13/22
The total number is:
12 (13 / 22-10 / 22) = 88 (tons)
Original grain storage in warehouse B:
88 × 10 / 22 = 40 (ton)

Solutions to Mathematical Olympiad problems
When summer came, Dad went to the store and bought four bottles of beer. The diameter of the bottom of the bottle was 7cm. The salesman tied the four bottles of beer together. How many meters does it take to tie them four times? (Tian shaped binding method)
If you buy three bottles of beer and tie them up, how many centimeters of rope should you use to tie them up three times?
For detailed answers, give 10 first, and then 45 for the good ones

First calculate how many centimeters a circle of four wine bottles. The figure formed by a circle of four wine bottles is similar to that of a square. There are four fans on the four corners. If you put the four fans together, it will be the circumference of a wine bottle: pi * 7cm. In addition, there are four sides, each side is 7cm. That is a straight diameter of the wine bottle. The four sides are 7 * 4 = 28cm in total, so

There are several numbers, the first one is A1, the second one is A2, the third one is A3, and the nth one is an. If A1 = 1 / 2, from the second number, each number is equal to the reciprocal of the difference between 1 and the number in front of it, then calculate A1, A2, A3, a2007

A1=1/2
A2=1/(1-A1)=1/(1-1/2)=1/(1/2)=2
A3=1/(1-A2)=1/(1-2)=-1
A4=1/(1-A3)=1/[1-(-1)]=1/2=A1
So a (n + 3) = an
So a2007 = a2004 = =A3=-1

Some simple mathematical problems! (see supplement) to have a complete process and answers!
9+99+999+9999+99999
199999+19999+1999+199+9
（1+3+5+… +1989）-（2+4+6+… +1988）
389+387+383+385+384+386+388
（4942+4943+4938+4939+4941+4943）\6
54+99*99+45
9999*2222+3333*3334
1999+999*999
Find the last zeros of (1988 * 9) * (1988 * 9) * (1988 * 9)

1.9+99+999+9999+99999=10+100+1000+10000+100000-1-1-1-1-1=111110-5=1111052.199999+19999+1999+199+9=200000+20000+2000+200+9-4=222200+5=2222053.（1+3+5+… +1989）-（2+4+6+… +1988）=(1-2)*995=-9954.389+387...

A simple mathematical olympiad in primary school
There is a number chain: "12345 12345 12345 12345.2345" to find the number truncated in front of 2345 may be ()
A: 2010 B: 2011 C: 2012 D: 2013 explain the reason, good simple bonus.

It should be B 2011
Because 12345 and 12345 are all groups of 5, that is to say, if the number intercepted is a multiple of 5, then the intercepted number is a whole group of 12345, and here is the. 2345 after intercepting, that is, intercepting a whole group of 12345 and adding a single 1
2010 is a multiple of 5, so it happens that 2010 is 402 groups, 12345 intercepts a 1
Do you understand? If you don't understand, you can ask me again~

Use a rope to measure the circumference of the tree. If you use the rope to circle the tree for five times, there will be 16 meters left. If you use the rope's 13 times to circle the tree, there will be 56 meters left. What are the circumference of the rope and the tree?

Let the perimeter of this tree be x meters, & nbsp; & nbsp; 5x + 16 = x △ 13 + 56, 5x + 16-3x = 3x + 56-3x, 2x + 16 − 16 = 56 − 16, & nbsp; & nbsp; 2x − 2 = 23 − 2, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 13, 5 × 13 + 16, = 53 + 16, = 156 (meters). A: the perimeter of this tree is 13 meters, and the length of the rope is 156 meters

(1) 2 + 2 to the 2nd power + 2 to the 3rd power +... + 2 to the 20th power =? Can't wait!
(1) 2 + 2 to the 2nd power + 2 to the 3rd power +... + 2 to the 20th power =? Can't wait!

4094.
This is a very basic sequence of equal proportion, just use the summation formula
Sn=n×a1 (q=1)
Sn=a1(1-q^n)/(1-q) =(a1-an×q)/(1-q) (q≠1)
Don't understand me

Terms without unknowns are called

Terms without unknowns are called
Constant term

calculation.
1、|-7+ 4| + (18) + |-6 —|
=
=
2、-99+100－97+98—95+96—… —1+2
=
=
Note - it's a minus sign

1、|-7+ 4| + (18) + |-6 —|
=3+18+6
=27
2、-99+100－97+98—95+96—… —1+2
=1+1+1..+1
=50

(‐3)­­‐(‐5)﹦
(‐3)‐5﹦

(‐3)­­‐(‐5)﹦(-3)+5=2
(‐3)‐5﹦(-3)+(-5)=-8