think about things at your school which have a negative
impact on the environment. what could you do to improve
these things? make a list of problems and solutions.
problems
a lot of students come to school by car. the cars pollute the air
outside the school.
solutions
find out which students live near each other. encourage them to
come to school together in the same car.
Пошаговое объяснение:
Обозначим красные воздушные шары - "К", зелёные - "З", синие - "С".
Пусть в коробке лежит х "К". ⇒ "З"=х/8 , а "С"≥1.
x+\frac{x}{8}+C=19.\ \ \ \ \ \ \ \ (1)x+
8
x
+C=19. (1)
Количество воздушных шаров - целое число. ⇒
\frac{x}{8}
8
x
- должно быть целым числом. Исходя из условия задачи х может равняться 8 и 16.
Подставляем х=8 в уравнение (1).
\begin{gathered}8+\frac{8}{8}+C=19\\8+1+C= 19\\9+C=19\\C=10.\end{gathered}
8+
8
8
+C=19
8+1+C=19
9+C=19
C=10.
Но по условию задачи "К">"C"≥1 ⇒ х≠8.
Подставляем х=16 в уравнение (1).
\begin{gathered}16+\frac{16}{8} +C=19\\16+2+C=19\\18+C=19\\C=1.\end{gathered}
16+
8
16
+C=19
16+2+C=19
18+C=19
C=1.
По условию задачи "К">"C"≥1 ⇒ x=16
A: What were you doing when the robbery took place?
B: I was standing in the queue.
A: What happened next?
B: Two men were pushing their way to the front. One of them was holding a gun.
A: Then what the men were doing?
B: They ordered the cashier to give them the money.
A: How did police find out about the robbery?
B: Well, the cashier set off the alarm while the robbers were putting the money in a bag.
A: And what happened when the police arrived?
B: The man with the gun dropped it, but it wasn't a real gun after all; it was a plastic one.
Объяснение: