Sorry it doesn't make sense. I mean it can't be calculated into a exact percentage cause it doesn't show the starting euros.

So I will calculate into an unknown starting money.

Call the starting money is x.

A company lost 97.940 million euros one year and next year gained 139.393 million euros, so the company ends up with \(x+41453\left(million-euros\right)\)

The final percentage of profit will be \(\dfrac{x+41453}{x}\cdot100\%\)

This answer depends on which x is the starting money.

Call the original size of the lens is x.

We have : The first lens multiplies the size by  and the second lens multiplies the size by .

We have: \(n\cdot180\%\cdot150\%=n\cdot\dfrac{9}{5}\cdot\dfrac{3}{2}=n\cdot\dfrac{27}{10}=n\cdot270\%\)

By \(270\%-100\%=170\%\) will the image be increased if the two lenses are used together.

Answer : 170%

The calendar's dates are present :

So when we reverse it, means   (reverse the order of the numbers in the second and the fourth rows).

So the difference : \(4+9+16+25-\left(1+10+17+22\right)=54-50=4\)

Answer : 4.

The product 201520162017 x 201820192020 have :

\(12+12-1=23\) (digits)

Answer : 23 digits.

From 234 x 5 = 1170

Then :

234 x 55 =12870

234 x 555 =129870.

So 234 x 66 digits 5 = 12(64 digits 9)870.

The sum of the digits of the product is : 1 + 2 + \(64\cdot9\) + 8 + 7 + 0 = 594.

Answer : 594.

Call the forgotten number is x.

Cause 17 numbers from 1 to n can't equal 599.

So it must be \(\dfrac{599\cdot4}{17\cdot4}\)\(=\dfrac{599}{17}\)=> this is the average of the numbers.

So the sum of 68 first numbers from 1 to 68 is 2346.

Cause he forgot a number so the sum must be 2346 + x.

The value of 599*4 = 2396.

So the missing number is 2396 - 2346 = 50.

The value of n is 69.

Có thể được hãy làm nhiều thứ tương tự như hoc24 :

- 2 CTV = Mathu selected this answer => đỡ hơn rất nhiều cho các Moderator phải online để .

* Các góp ý khác :

- Sử dụng địa chỉ email thật để đăng kí tài khoản => Tránh 1 tài khoản lập nhiều nick.

- CTV có quyền xóa câu hỏi, câu trả lời không đúng chủ đề trang web.

- Tuyển hoặc thuê người viết quy luật, nội quy cho web => chưa có nội quy cụ thể.

- Áp dụng thuật toán dịch tự động bài Tiếng Việt qua Tiếng Anh (nếu có) cho nhiều bạn yếu môn TA, đặc biệt Toán TA để tham gia hỏi đáp trên diễn đàn.

- Bổ sung chức năng nhắn tin nhóm => thuận lợi cho việc trao đổi tập thể.

- Bổ sung chức năng Thông báo => Hiện thông báo người nào cho mình, người nào tag mình ...

- Chính thức công bố chức năng "BADGES" (nếu có thể).

- Dán bảng thưởng tuần/tháng lên thẳng trang web, không phải mất công qua olm để lấy link.

....

Đấy là ý kiến của mình, mong các CTV và moderator xem xét :)

Thân :)

\(\dfrac{1}{11}\cdot\left(17-3\sqrt{x-1}\right)=\dfrac{1}{15}\cdot\left(23-4\sqrt{x-1}\right)\)

Condition \(x\ge1\)

\(\Leftrightarrow\dfrac{17}{11}-\dfrac{3\sqrt{x-1}}{11}=\dfrac{23}{15}-\dfrac{4\sqrt{x-1}}{15}\)

\(\Leftrightarrow\dfrac{17}{11}-\dfrac{23}{15}=-\dfrac{4\sqrt{x-1}}{15}+\dfrac{3\sqrt{x-1}}{11}\)

\(\Leftrightarrow\dfrac{2}{165}=\dfrac{-44\sqrt{x-1}+45\sqrt{x-1}}{165}\)

\(\Rightarrow2=\sqrt{x-1}\)

\(\Leftrightarrow4=x-1\Rightarrow x=5\) (satisfy with condition)

Hence, \(S=\left\{5\right\}\)

\(\left(7+\sqrt{x}\right)\cdot\left(8-\sqrt{x}\right)=x+11\)

Condition \(x\ge0\)

\(\Leftrightarrow56-7\sqrt{x}+8\sqrt{x}-x=x+11\)

\(\Leftrightarrow-2x+\sqrt{x}+56=11\)

\(\Leftrightarrow-\left(\sqrt{x}-5\right)\cdot\left(2\sqrt{x}+9\right)=0\)

Cause \(x\ge0\Rightarrow2\sqrt{x}+9>0\forall x\ge0\)

So \(\sqrt{x}-5=0\Rightarrow x=25\) (satisfy with condition)

Hence, \(S=\left\{25\right\}\)

\(\sqrt{2+\sqrt{3+\sqrt{x}}}=3\)

Condition \(x\ge0\)

\(\Leftrightarrow\left(\sqrt{2+\sqrt{3+\sqrt{x}}}\right)^2=3^2\)

\(\Leftrightarrow2+\sqrt{3+\sqrt{x}}=9\)

\(\Leftrightarrow\sqrt{3+\sqrt{x}}=7\)

\(\Leftrightarrow3+\sqrt{x}=49\)

\(\Leftrightarrow\sqrt{x}=46\Rightarrow x=46^2=2116\) (satisfy with condition).

Hence, \(S=\left\{2116\right\}\)

This is easy man :v you just double it up ~`~

\(1+\sqrt{2x}=10\)

Condition \(x\ge0\)

\(\Leftrightarrow\sqrt{2x}=9\)

\(\Leftrightarrow\left(\sqrt{2x}\right)^2=9^2\)

\(\Leftrightarrow2x=81\left(2x\ge0\right)\)

\(\Rightarrow x=\dfrac{81}{2}\) (satisfy with condition)

Hence, \(S=\left\{\dfrac{81}{2}\right\}\)

\(x^2+y^2=2500\)

Same with \(x^2+y^2=50^2\) (Pythagorean's theorem)

We know that : A Pythagorean triple consists of three positive integers a, b, and c, such that a² + b² = c². And a,b,c MUST be rational.

Cause there is no Pythagorean triple x;y which x;y are rational and satisfy \(x^2+y^2=50^2\)

So there aren't any ordered pairs of integers (x, y) satisfy the equation \(x^2+y^2\) = 2500 .

Answer : 0 ordered pair.

Next time please write in English.

I will help you this time.

Because it's a square, so the area is \(\dfrac{1}{2}\cdot\dfrac{1}{2}=\dfrac{1}{4}\left(m^2\right)\)

\(\dfrac{1}{3}\) area of that square has the value of \(\dfrac{1}{4}\cdot\dfrac{1}{3}=\dfrac{1}{12}\left(m^2\right)\)

Answer : \(\dfrac{1}{12}m^2\)

In thread we have : The integers 1 through 6 be written horizontally in a row so that the sum of any two adjacent integers is odd.

So there will be \(3\cdot3\cdot2\cdot2\cdot1\cdot1=36\) ways.

Answer : 36 ways.

Following thread we have :

A party with 25 guests = 2 x (A party with 10 guests). (1)

A party with n guests = 2 x (A party with 25 guests). (2)

So the value of n is :

Put (2) in (1) we have : A party with n guests = 4 x (A party with 10 guests).

\(\Rightarrow\dfrac{n}{4}=10\Rightarrow n=40\), So the value of n is 40.

Answer : 40.

Following thread we have :

15 teams in a soccer league.

1 team : 8 games/season.

So the total number of games played is \(SUM=\dfrac{15\cdot8}{2}=60\left(games\right)\)during the season.

Following thread we have :

Mrs. Lowe is buying lunch for her class of 25 students.

A large pizza : 3 people / 8$.

A giant sub :  4 people / 9$.

So we will buy 3 large pizzas for 9 people, and 4 giant subs for 16 people.

The sum will be : \(3\cdot8+4\cdot9=60\)$ => the least amount it will cost Mrs. Lowe to feed all the students in her class.

The product \(2,4999\cdot3,9999\cdot4,9999=49,99575011\)

So the smallest interger that is greater than the product is \(50\)

Following thread we have :

2,40$ : First quarter of a mile.

So there will be \(10-2,40=7,60\)$ left.

Next, it charges 0,40$ : each additional fifth of a mile.

So that's enough to travel \(\dfrac{7,60}{0,40}=19\) fifths of a mile.

The total miles can a rider travel is : \(\dfrac{1}{4}+\dfrac{19}{5}=\dfrac{81}{20}=4,05\left(miles\right)\)

\(FACT\left(299\right)=13\cdot23\)

Cause the members are \(2< members< 20\)

So the members of the local gaming club must be 13, and a signed copy of the latest book from the legendary Dumas costs 23 dollars.

Answer : 13 members.