Question

Вкладчик добавил на свой счет 64 рубля, после чего дважды снимал по 10% от имеющей суммы. В результате чего на его счету оказалось 64,8 рубля. Определить первоначальный вклад.

Answer 1

Х рублей - первоначальный вклад

((х + 64) * 0,9) * 0,9 = 64,8
х = (64,8 : 0,9) : 0,9 - 64
х = 16 рублей - первоначальный вклад

Answer 2

Problem Analysis

The problem states that a depositor added 64 rubles to their account and then withdrew 10% of the total amount twice. As a result, the account balance was 64.8 rubles. We need to determine the initial deposit amount.

Solution

Let's assume the initial deposit amount is x rubles.

According to the problem, the depositor added 64 rubles to their account. Therefore, the total amount in the account after the deposit is x + 64 rubles.

Next, the depositor withdrew 10% of the total amount twice. This means they withdrew 10% of x + 64 rubles twice.

The equation representing the withdrawals can be written as:

x + 64 - (0.1 * (x + 64)) - (0.1 * (x + 64)) = 64.8

Simplifying the equation:

x + 64 - 0.1x - 6.4 - 0.1x - 6.4 = 64.8

Combining like terms:

x - 0.2x + 64 - 6.4 - 6.4 = 64.8

Simplifying further:

0.6x + 51.2 = 64.8

Subtracting 51.2 from both sides:

0.6x = 13.6

Dividing both sides by 0.6:

x = 22.67

Therefore, the initial deposit amount was approximately 22.67 rubles.

Conclusion

The initial deposit amount was approximately 22.67 rubles.