Question

в девятых и десятых классах школы 162 ученика. число учащихся десятых классов составляет 80% числа учащихся девятых классов. сколько в школе девятиклаасников и сколько десятиклассников?

Answer 1

принимаем число девятиклассников за x, тогда десятиклассников- x*80%=0.8x.

значит всего учеников - x+0.8x=1.8x или по условию задачи-162, значит девятиклассников - х=162/1.8=90, значит десятикласников- 0.8*90=72.

Answer 2

Solution:

To solve this problem, we can use the information given about the total number of students in the 9th and 10th grades and the ratio between them.

Let's denote: - Total number of students in the school: 162 - Number of 9th-grade students: x - Number of 10th-grade students: 0.8x (80% of the number of 9th-grade students)

We know that the total number of students in the school is 162, so we can set up the equation:

x + 0.8x = 162

Solving for x:

1.8x = 162 x = 162 / 1.8 x = 90

So, the number of 9th-grade students is 90, and the number of 10th-grade students is 0.8 * 90 = 72.

Answer:

- Number of 9th-grade students: 90 - Number of 10th-grade students: 72