Question

Ученик рассчитывал за 1 5/6 часа приготовить уроки и за 1 3/4ч закончить модель корабля. однако на всё работу он потратил на 2/5 ч меньше, чем предполагал . сколько времени потратил ученик на всё работу?

Answer 1

Придется доли часа перевести в минуты.  1 час = 60 минут.
1 5/6 ч = 1 ч  5*10 мин = 1 ч 50 мин. - уроки
1 3/4 ч =1ч  3*15 мин =  1ч 45 мин - моделирование.
Время по плану.
1 ч 50 мин + 1 ч 45 мин = 2 ч 95 мин = 3 ч 35 мин
Сделал быстрее на
2/5 ч = 2*12 мин = 24 мин 
Работал фактически
3 ч 35 мин - 24 мин = 3 ч 11 мин - ОТВЕТ

Answer 2

Time Spent on Each Task

The student planned to spend 1 5/6 hours on preparing lessons and 1 3/4 hours on finishing a model ship. However, he ended up spending 2/5 hours less than he had planned.

The total time the student planned to spend on both tasks can be calculated as follows: - Time for preparing lessons: 1 5/6 hours = 11/6 hours - Time for finishing the model ship: 1 3/4 hours = 7/4 hours

Calculation of Total Time Spent

To find out how much time the student actually spent on both tasks, we can calculate the total time he planned to spend and then subtract 2/5 hours from it.

The total time the student planned to spend on both tasks is: 11/6 hours + 7/4 hours

To simplify the calculation, we can find a common denominator for 6 and 4, which is 12.

Converting 11/6 to have a denominator of 12: 11/6 = 22/12

Converting 7/4 to have a denominator of 12: 7/4 = 21/12

So, the total time the student planned to spend on both tasks is: 22/12 hours + 21/12 hours = 43/12 hours

Subtracting 2/5 hours from the total planned time: 43/12 hours - 2/5 hours

Calculation of Total Time Spent (Continued)

To subtract 2/5 hours from 43/12 hours, we need to find a common denominator for 12 and 5, which is 60.

Converting 43/12 to have a denominator of 60: 43/12 = 215/60

Converting 2/5 to have a denominator of 60: 2/5 = 24/60

Subtracting 24/60 from 215/60: 215/60 - 24/60 = 191/60

So, the total time the student actually spent on both tasks is: 191/60 hours

Conclusion

Therefore, the student spent 191/60 hours on both tasks, which can be simplified to 3 11/60 hours or approximately 3.183 hours.