Question

1)9,88:(6,7 - x)=2,6 2)14+6,2a+2,4a=69,9 3)В олимпиаде по математике участвовали 120 учащихся пятых и шестых классов. Пятиклассники составляют 55% всех участников. Сколько пятиклассников приняло участие в олимпиаде?

Answer 1

1)9,88:(6,7 - x)=2,6

6.7-х=9.88:2.6

6.7-х=3.8

-х=3.8-6.7

-х=-2.9

х=2.9

 

2)14+6,2a+2,4a=69,9 

8.6а=69.9-14

8.6а=55.9

а=55.9:8.6

а=6.5

 

№3

1)120:100*55=66уч-пятиклассников.

Answer 2

Задание 2

6.2а+2.4а=-14+69.9

8.6а=55.9

а=6.5

Задание 3

120:100*55=66 пятиклассников

Answer 3

1. To solve the equation 9.88 / (6.7 - x) = 2.6, we can follow these steps:

9.88 / (6.7 - x) = 2.6

Multiply both sides of the equation by (6.7 - x):

9.88 = 2.6 * (6.7 - x)

Distribute the 2.6:

9.88 = 17.42 - 2.6x

Rearrange the equation by isolating the term with x:

2.6x = 17.42 - 9.88

2.6x = 7.54

Divide both sides by 2.6 to solve for x:

x = 7.54 / 2.6

x ≈ 2.9

Therefore, the value of x in the equation is approximately 2.9.

2. To solve the equation 14 + 6.2a + 2.4a = 69.9, we can follow these steps:

Combine like terms:

14 + 6.2a + 2.4a = 69.9

Combine the coefficients of 'a':

14 + 8.6a = 69.9

Subtract 14 from both sides of the equation:

8.6a = 69.9 - 14

8.6a = 55.9

Divide both sides by 8.6 to solve for a:

a = 55.9 / 8.6

a ≈ 6.50

Therefore, the value of a in the equation is approximately 6.50.

3. Let's denote the number of fifth-grade students as 'x'. Since fifth-grade students make up 55% of all participants, the number of sixth-grade students would be (100% - 55%) = 45% of all participants.

The total number of participants in the Olympiad is 120, so we can set up the equation:

x + 0.45x = 120

Simplify the equation:

1.45x = 120

Divide both sides by 1.45 to solve for x:

x = 120 / 1.45

x ≈ 82.76

Therefore, approximately 82.76 fifth-grade students participated in the Olympiad.