Question

На вопрос "Который час?"- один шутник ответил:"Половина времени,прошедшего после полуночи,равно 3/4 времени,оставшегося до полудня".Который тогда был час? P.S.В ответах написано 18 часов,но у меня никак не получается.

Answer 1

От полуночи до полудня проходит 12 часов
пусть до полудня будет х ч
тогда после полночи прошло у ч
составляем уравнение
х+у=12 
у=12-х
у/2=3/4 х
(12-х)/2=3/4 х
12-х=3/4 х *2
12-х=3/2 х
12=1 1/2 х+х
12= 2 1/2 х = 
х=12: 2 1/2
х=12:5/2
х=24/5= 4 4/5 ч
4/5 ч = 60:5*4=48 мин
значит до полудня осталось 4 часов 48 минут или 4.8 часов
12-4.8=7.2 часов - прошло от полночи
0.2 ч = 12 мин
значит от полночи прошло 7 часов12 минут
если учесть. что после полночи отсчет начинается с нуля, то на часах было
7 часов 12 минут

Answer 2

The Riddle

The riddle states that when someone was asked for the time, they responded with the following statement: "Half of the time that has passed since midnight is equal to three-fourths of the time remaining until noon." The question is, what time was it when this statement was made?

Solving the Riddle

To solve this riddle, we need to break down the statement and find a time that satisfies the given conditions.

Let's assume that the time when the statement was made is x hours after midnight. According to the statement, half of the time that has passed since midnight is equal to three-fourths of the time remaining until noon.

The time that has passed since midnight is x hours, and the time remaining until noon is 12 - x hours. So, we can write the equation as:

x/2 = (3/4)(12 - x)

To solve this equation, we can multiply both sides by 4 to get rid of the fraction:

4(x/2) = 4(3/4)(12 - x)

Simplifying further:

2x = 3(12 - x)

Expanding the equation:

2x = 36 - 3x

Combining like terms:

5x = 36

Dividing both sides by 5:

x = 7.2

Therefore, the time when the statement was made was 7.2 hours after midnight. However, since time is typically measured in whole hours, we can round this to the nearest hour.

So, the answer to the riddle is that the time was approximately 7 hours when the statement was made.

Conclusion

The riddle asked for the time when a person made a statement about the relationship between the time passed since midnight and the time remaining until noon. By solving the equation derived from the statement, we found that the time was approximately 7 hours when the statement was made.