Question

Артур хочет купить машинки (все они стоят одинаково). Если он купит семь машинок, то у него останется 100 руб., а до покупки девяти машинок у него не хватает 20 руб. Сколько стоит одна машинка?

Answer 1

1) 9-7=2 машинки разница между первой и второй покупкой
2) 100+20=120 рублей разница между покупкой 9 и 7 машинок
3) 120:2=60 рублей стоит 1 машинка

Ответ 60 рублей

Answer 2

Arthur's Dilemma: How much does one toy car cost?

Arthur wants to buy toy cars, and they all cost the same amount. If he buys seven toy cars, he will have 100 rubles left. However, if he wants to buy nine toy cars, he is short by 20 rubles. The question is, how much does one toy car cost?

To solve this problem, let's break it down step by step:

1. Let's assume the cost of one toy car is x rubles.

2. If Arthur buys seven toy cars, he will have 100 rubles left. This can be expressed as the equation: 7x + 100 = total amount of money Arthur has.

3. If Arthur wants to buy nine toy cars, he is short by 20 rubles. This can be expressed as the equation: 9x - 20 = total amount of money Arthur has.

Now, we can solve these equations to find the value of x, which represents the cost of one toy car.

To solve the equations, we can use a method called substitution. We'll solve the first equation for x and substitute it into the second equation.

Solving the equations:

1. From the first equation, we have: 7x + 100 = total amount of money Arthur has.

2. Solving for x, we subtract 100 from both sides: 7x = total amount of money Arthur has - 100.

3. Simplifying further, we have: 7x = total amount of money Arthur has - 100.

4. Now, let's substitute this value of 7x into the second equation: 9(total amount of money Arthur has - 100) - 20 = total amount of money Arthur has.

5. Expanding the equation, we have: 9(total amount of money Arthur has) - 900 - 20 = total amount of money Arthur has.

6. Simplifying further, we have: 9(total amount of money Arthur has) - 920 = total amount of money Arthur has.

7. Combining like terms, we have: 8(total amount of money Arthur has) = 920.

8. Solving for total amount of money Arthur has, we divide both sides by 8: total amount of money Arthur has = 920 / 8.

9. Calculating the value, we find: total amount of money Arthur has = 115 rubles.

Now that we know the total amount of money Arthur has, we can substitute it back into the first equation to find the cost of one toy car.

10. Substituting the value of total amount of money Arthur has into the first equation, we have: 7x + 100 = 115.

11. Solving for x, we subtract 100 from both sides: 7x = 115 - 100.

12. Simplifying further, we have: 7x = 15.

13. Finally, solving for x, we divide both sides by 7: x = 15 / 7.

14. Calculating the value, we find: x ≈ 2.14 rubles.

Therefore, one toy car costs approximately 2.14 rubles.

Please note that the calculations are based on the given information and assumptions made.