Solution: Suppose it takes X days to actually complete the production task.

According to the meaning: 7200*( 1+20%) divided by x=720.

Simplification:12/x-10/(x+4) =1.

Denominator:12 (x+4)-10x = x (x+4).

Ordered: x2+2x-48 = 0.

Solution: x 1=6, x2=-8 (irrelevant, omitted)

∴ 7200× (1+20%) ÷ 6 =1440 (on)

Answer: The factory actually produces 1440 tents every day.

2. Let the primitive number be100000x+y..

Where x is a number.

Y is five digits.

3( 100000x+y)= 10y+x

299999x=7y

42857x=y

When x= 1

y=42857

So the original number is 142857.

3. Solution: Let one set of purchase price be M yuan and the other set of purchase price be N yuan. According to the meaning of the question, m (1+10%) = n (1-10%).

……

(1), solution, m=0.9/ 1. 1n, sum of two selling prices/sum of two buying prices after price adjustment = (1.1m+0.9n)/(m+n) de( 1. 1 * 0.9/ 1. 1n+0.9n)/(0.9/ 1. 1n+n)= 0.99 1-0.99 = 0.066。

4. We form a party team, with one classmate in one row and one classmate in the other.

So the total number of students is a×a+7.

Meaning of the question (a× a+7)/8 = a → (a-7) (a-1) = 0 → a = 7. A = 1 does not meet the meaning of the question and is discarded.

So a=7

Then the whole class is 7×7+7=56 students.

5. Set the concentration X of A, the concentration Y of B, and pour out the weight Z..

Judging from the meaning of the question: (ZX+Y(60-Z))/60=(YZ+X(40-Z))/40.

Finishing 5Z= 120

So Z=24.