Cô lan Gửi 17tr đồng vào ngân hàng trong đó có 2 loại tiền là 50k và 100k. có tất cả 250 tờ. Hỏi mỗi loại tiền có bao nhiêu tờ?:(((

1 câu trả lời

$\text{Gọi số tờ mỗi loại lần lượt là x và y (x, y ∈ N*; Tờ)}$

$\text{Có tất cả 250 tờ nên ta có phương trình: x + y = 250 (Tờ) (1)}$

$\text{Cô Lan gửi 17000000 đồng vào ngân hàng trong đó có 2 loại tiền}$

$\text{là 50000 đồng và 100000 đồng nên ta có phương trình:}$

$\text{50000x + 100000y = 17000000 (Đồng) (2)}$

$\text{Từ (1)(2) ta có hệ phương trình:}$

$\text{$\begin{cases} x + y = 250\\50000x + 100000y = 17000000 \end{cases}$}$

$\text{⇔ $\begin{cases} x = 250 - y\\50000(250 - y) + 100000y = 17000000 \end{cases}$}$

$\text{⇔ $\begin{cases} x = 250 - y\\12500000 - 50000y + 100000y = 17000000 \end{cases}$}$

$\text{⇔ $\begin{cases} x = 250 - y\\50000y = 4500000 \end{cases}$}$

$\text{⇔ $\begin{cases} x = 250 - 90 = 160 (t/m)\\y = 90 (t/m) \end{cases}$}$

$\text{Vậy tờ tiền loại 50000 đồng có 160 tờ; tờ tiền loại 100000 đồng có 90 tờ}$

$\textit{Ha1zzz}$

 

Câu hỏi trong lớp Xem thêm

I.  MULTIPLE CHOICE (8.0 points)

Mark the letter A, B, C, or D to indicate the word whose underlined part is pronounced differently front that of the rest in each of the following questions.

1. A. oceanic    B. remote    C. occasion    D. metro

2. A. festival    B. cultural    C. sculpture    D. virtual

Mark the letter A, B, C, or D to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

3. A. external    B. determine    C. mysterious    D. customer

4. A. miraculous    B. individual    C. certificate    D. astronomy

Mark the letter A, B, C, or D to indicate the underlined part that needs correction in each of the following questions.

5. Now that the stress of examinations are over, we can go somewhere for our holiday.

                     A                     B                     C                     D

6. The English summer course will start in May 29th and finish in August.

                     A                     B                     C                     D

7. There were so a lot of people trying to leave the burning building that the police

             A                B             C

had a great deal of trouble controlling them.

                   D

Mark the letter A, B, C, or D to indicate the correct answer to each of the following questions.

8. The earthworm is a worm _______in moist, warm soil in many geographical areas.

    A. where is it found       B. is found

    C. and found it               D. which is found

9. Our flight from Amsterdam to London was delayed    the heavy fog.

    A. as a result     B. on account     C. instead of     D. due to

10. It is_______ to translate each lesson into your language. This is not a good way to study English.

    A. productive     B. unproductive     C. producing     D. unproducing

11. A good clock always keeps_______ time.

    A. certain    B. accurate    C. true    D. serious

12. It seems that the world record for this event is almost impossible to_______.

    A. meet    B. compare    C. beat    D. balance

13. The soldier was punished for_______ to obey his commanding officer's order.

    A. refusing    B. regretting    C. objecting    D. resisting

14. It is believed that she'll be a billionaire by the time she_______ forty.

    A. is    B. was    C. will be    D. would be

15. Some of the passengers spoke to reporters about their_______ in the burning bus.

    A. occasion    B. happening    C. event    D. experience

16. _______the rise in unemployment, people still seem to be spending more.

    A. Nevertheless    B. Meanwhile    C. Despite    D. Although

5 lượt xem
1 đáp án
13 giờ trước