Question

незнайка хотел купить 5 порций мороженого но ему не хватило 60 рублей. тогда он купил две порции мороженого и у него осталось 90 рублей. сколько было денег у незнайки сначала?

Answer 1

Пусть х руб. - цена одной порции мороженого. Уравнение:

5 · х - 60 = 2 · х + 90

5х - 2х = 90 + 60

3х = 150

х = 150 : 3

х = 50 (руб.) - цена одной порции мороженого

5 · 50 - 60 = 2 · 50 + 90

250 - 60 = 100 + 90

190 = 190 (руб.) - столько денег было у Незнайки.

Ответ: 190 руб.

Answer 2

Problem Analysis

Neznayka wanted to buy 5 portions of ice cream but was short of 60 rubles. He then bought two portions of ice cream and had 90 rubles left. We need to determine how much money Neznayka had initially.

Solution

Let's assume that Neznayka initially had x rubles.

According to the given information, Neznayka was short of 60 rubles to buy 5 portions of ice cream. This means that the cost of 5 portions of ice cream is 60 rubles more than what Neznayka had initially.

After buying two portions of ice cream, Neznayka had 90 rubles left. This means that the cost of two portions of ice cream is equal to the difference between what Neznayka had initially and what he had left.

We can set up the following equations based on the given information:

Equation 1: x + 60 = 5p, where p is the cost of one portion of ice cream. Equation 2: x - 2p = 90

To solve these equations, we can substitute the value of p from Equation 1 into Equation 2 and solve for x.

Let's solve the equations:

Equation 1: x + 60 = 5p Equation 2: x - 2p = 90

Substituting the value of p from Equation 1 into Equation 2: x - 2(60 - x/5) = 90 x - 120 + 2x/5 = 90 5x - 600 + 2x = 450 7x = 1050 x = 150

Therefore, Neznayka initially had 150 rubles.

Answer

Neznayka initially had 150 rubles.