Question

Сумму 140 руб, можно составить пятирублевыми и двухрублевыми монетами, причём пятирублевых монет взять столько же, сколько и двухрублевых. Сколько нужно пятирублевых монет?

Answer 1

х-по столько монет нужно взять

5*х+2*х=140

7х=140

х=20 монет 

5*20+2*20=140 рублей

Answer 2

Problem Analysis

To solve this problem, we need to find the number of five-ruble coins required to make a total of 140 rubles using both five-ruble and two-ruble coins. The number of five-ruble coins should be the same as the number of two-ruble coins.

Solution

Let's assume the number of five-ruble coins required is 'x'. Since the number of five-ruble coins is the same as the number of two-ruble coins, we can also say that the number of two-ruble coins required is 'x'.

The value of each five-ruble coin is 5 rubles, and the value of each two-ruble coin is 2 rubles. Therefore, the total value of the five-ruble coins is 5x rubles, and the total value of the two-ruble coins is 2x rubles.

According to the problem, the sum of the values of the five-ruble and two-ruble coins should be 140 rubles. We can write this as an equation:

5x + 2x = 140

Simplifying the equation, we get:

7x = 140

To find the value of 'x', we divide both sides of the equation by 7:

x = 20

Therefore, we need 20 five-ruble coins to make a total of 140 rubles using both five-ruble and two-ruble coins.

Answer

To make a total of 140 rubles using both five-ruble and two-ruble coins, you will need 20 five-ruble coins.