Question

После того как Сергей потратил три пятых своих денег , у него осталось 90 рублей . Сколько денег потратил Сергей?

Answer 1

5/5-3/5=2/5   - это 90 рублей
90/2*5=225 рублей было 
225-90=135 рублей потратил

2 способ

5/5-3/5=2/5   - это 90 рублей
90/2*5=225 рублей было 
225/5*3=135 рублей (3/5) потратил

3 способ

90 рублей - это 2 части
90/2=45 рублей - 1 часть
45*3=135 рублей - это 3/5  - потратил

Answer 2

5/5- 3/5 =2/5 = 90 
1/5 =45р.
3/5 =45+45+45 =135
он потратил 135 р.

Answer 3

Calculation of Sergei's Expenses

To calculate how much money Sergei spent, we can use the information provided in the question. It states that after spending three-fifths of his money, Sergei had 90 rubles left.

Let's break down the calculation step by step:

1. Let's assume Sergei initially had x rubles. 2. Sergei spent three-fifths of his money, which is equal to (3/5) * x. 3. After spending (3/5) * x, Sergei had 90 rubles left.

To find out how much money Sergei spent, we need to solve the equation:

x - (3/5) * x = 90

Simplifying the equation:

(2/5) * x = 90

To isolate x, we can multiply both sides of the equation by 5/2:

x = 90 * (5/2)

Now we can calculate Sergei's expenses:

x = 225

Therefore, Sergei initially had 225 rubles, and he spent 225 - 90 = 135 rubles.

Answer: Sergei spent 135 rubles.