Question

В бак объёмом 38 литров каждый час, начиная с 12 часов, наливают полное ведро воды объёмом 8 литров. Но в днище бака есть небольшая щель, и из неё за час вытекает 3 литра. В какой момент времени (в часах) бак будет заполнен полностью?

Answer 1

(8-3)*х+8=38
8х-3х+8=38
5х+8=38
5х=38-8
5х=30
х=6 часов до полного бака
12+6=18
ответ:в 18 часов

Answer 2

Problem Analysis

We have a tank with a volume of 38 liters. Every hour, starting from 12 o'clock, we pour a full bucket of water with a volume of 8 liters into the tank. However, there is a small gap in the bottom of the tank from which 3 liters of water leak out every hour. We need to determine at what time (in hours) the tank will be completely filled.

Solution

To solve this problem, we can calculate the net increase in water volume per hour and keep track of the total volume of water in the tank until it reaches 38 liters.

Let's break down the problem step by step:

1. At 12 o'clock, we pour a full bucket of water with a volume of 8 liters into the tank. 2. However, 3 liters of water leak out of the tank every hour. 3. So, the net increase in water volume per hour is 8 liters (bucket volume) minus 3 liters (leakage) = 5 liters. 4. We need to keep pouring water into the tank until it reaches a total volume of 38 liters.

Now, let's calculate the time it takes to fill the tank:

- At 12 o'clock, the tank has a volume of 8 liters. - After the first hour, the tank volume increases to 8 + 5 = 13 liters. - After the second hour, the tank volume increases to 13 + 5 = 18 liters. - After the third hour, the tank volume increases to 18 + 5 = 23 liters. - After the fourth hour, the tank volume increases to 23 + 5 = 28 liters. - After the fifth hour, the tank volume increases to 28 + 5 = 33 liters. - After the sixth hour, the tank volume increases to 33 + 5 = 38 liters.

Therefore, it takes 6 hours for the tank to be completely filled.

Answer: The tank will be completely filled in 6 hours.