Question

Помогите пожалуйста решить задачу. В парке растут берёзы, осины, ели и рябины. Берёз на 18 больше чем осин, осин в 2 раза больше чем елей, а рябин на 6 меньше чем елей. Сколько в парке берёз если всего 138 деревьев?

Answer 1

Ответ:

Фото

Объяснение:

Answer 2

Пусть x – все ели, посаженные в парке; тогда рябин x - 6;  осин 2x; берёз 2x + 18

Зная, что всего в парке растёт 138 деревьев, составим уравнение:

$x+(x-6)+2x+(2x+18)=138\\\\x+x-6+2x+2x+18=138\\\\6x=138+6-18\\\\6x=126\\\\x=126:6$

$x=21$  (елей) – растёт в парке

$21\cdot2+18=60$ (берёз) – растёт в парке

Ответ: 60 берёз

Answer 3

Problem Analysis

To solve this problem, we need to determine the number of birch trees in the park given the total number of trees and the relationships between the different types of trees. Let's break down the information provided:

- The number of birch trees is 18 more than the number of aspen trees. - The number of aspen trees is twice the number of spruce trees. - The number of rowan trees is 6 less than the number of spruce trees.

We are also given that the total number of trees in the park is 138.

Solution

Let's assign variables to represent the number of each type of tree: - Let B represent the number of birch trees. - Let A represent the number of aspen trees. - Let S represent the number of spruce trees. - Let R represent the number of rowan trees.

We can now translate the given information into equations:

1. The number of birch trees is 18 more than the number of aspen trees: B = A + 18. 2. The number of aspen trees is twice the number of spruce trees: A = 2S. 3. The number of rowan trees is 6 less than the number of spruce trees: R = S - 6. 4. The total number of trees is 138: B + A + S + R = 138.

We can now solve this system of equations to find the values of B, A, S, and R.

Solving the System of Equations

Let's substitute the values from equations 2 and 3 into equation 4 to eliminate A and R:

B + (2S) + S + (S - 6) = 138

Simplifying the equation:

B + 4S - 6 = 138

Rearranging the equation:

B + 4S = 144 (Equation 5)

Now, let's substitute the value from equation 2 into equation 1 to eliminate A:

B = (2S) + 18 (Equation 6)

We can now substitute the value from equation 6 into equation 5:

(2S) + 18 + 4S = 144

Simplifying the equation:

6S + 18 = 144

Subtracting 18 from both sides:

6S = 126

Dividing both sides by 6:

S = 21

Now that we have the value of S, we can substitute it back into equation 6 to find B:

B = (2 * 21) + 18

Simplifying the equation:

B = 42 + 18

B = 60

Therefore, there are 60 birch trees in the park.

Answer

There are 60 birch trees in the park if there are a total of 138 trees.