−2.8x+5.6<8.4 please help

There are 158 students registered for American History classes. There are twice as many students registered in second period as

Margarita [4]

There are 28 students in first period and 56 students in sceond period and 74 students in third period

Solution:

Let the number of students in first period be "x"

Let the number of students in second period be "y"

Let the number of students in third period be "z"

There are 158 students registered for American History classes.

Therefore,

x + y + z = 158 ---------- eqn 1

There are twice as many students registered in second period as first period

number of students in second period = twice of number of students in first period

y = 2x ------- eqn 2

There are 10 less than three times as many students in third period as in first period

number of students in third period = 3 times number of students in first period - 10

z = 3x - 10 ------ eqn 3

Substitute eqn 2 and eqn 3 in eqn 1

x + 2x + 3x - 10 = 158

6x = 168

Substitute x = 28 in eqn 2

y = 2(28)

Substitute x = 28 in eqn 3

z = 3(28) - 10

z = 84 - 10

Thus there are 28 students in first period and 56 students in sceond period and 74 students in third period

5 0

2 years ago

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snow_tiger [21]

Answer:

What the what???????

4 0

3 years ago

Read 2 more answers

When Arianna left her house,her cell phone was 45% charged started losing charge at a constant rate. 4 hours after leaving her h

4vir4ik [10]

Answer:

B = 3.75t

Step-by-step explanation:

Given;

initial charge of Arianna's phone = 45%

the charge remaining in Arianna battery = 15%

If after 4hours of leaving her house, the battery had 15% remaining battery life, then the battery is discharging at the rate of ( 15% / 4hours) 3.75% per hour.

Thus, the charge remaining in Arianna's battery after she left her house is given by;

B = 3.75t

where;

t is time in hours

B is the percentage of charge remaining

6 0

3 years ago

Please help me with NUMBER 7 !! Thank you so much! 20 points!! :))

mart [117]

Answer:

x<-3 or x>-1

Step by step explanation:

Start with -5x>15. To get x by itself, we have to divide each side by -5. When we do that we get x<-3. (Don't forget to flip the sign when dealing with negative · and ÷.) Now answer the second equation. x-5>-6 To get x by itself, add 5 to both sides to get x>-1. Now we have x<3 or x>-1.

8 0

3 years ago

Find the equation of the circle with center at (-1, 3) and radius of 4.

Nataly [62]

Answer:

(x+1)^2 + (y-3)^2 = 16

Step-by-step explanation:

The equation of a circle is given by

(x-h)^2 + (y-k)^2 = r^2

Where (h,k) is the center and r is the radius

(x--1)^2 + (y-3)^2 = 4^2

(x+1)^2 + (y-3)^2 = 4^2

(x+1)^2 + (y-3)^2 = 16

7 0

2 years ago