The number of students in 5th grade is 60, since 24% of 250 is 60.
Since 90 is 38% if 250, 38 is going to be the percent of all students in sixth grade.
20% of 250 is 50, so the percent of all students in seventh grade is 50.
Finally, 45 is 18% of 250, so 18 percent of all students are in eight grade.
Hope this helped :)
General Idea:
(i) Assign variable for the unknown that we need to find
(ii) Sketch a diagram to help us visualize the problem
(iii) Write the mathematical equation representing the description given.
(iv) Solve the equation by substitution method. Solving means finding the values of the variables which will make both the equation TRUE
Applying the concept:
Given: x represents the length of the pen and y represents the area of the doghouse
<u>Statement 1: </u>"The pen is 3 feet wider than it is long"

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<u>Statement 2: "He also built a doghouse to put in the pen which has a perimeter that is equal to the area of its base"</u>

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<u>Statement 3: "After putting the doghouse in the pen, he calculates that the dog will have 178 square feet of space to run around inside the pen."</u>

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<u>Statement 4: "The perimeter of the pen is 3 times greater than the perimeter of the doghouse."</u>

Conclusion:
The systems of equations that can be used to determine the length and width of the pen and the area of the doghouse is given in Option B.

Answer:
$14.23
Step-by-step explanation:
Multiply the original value by 1.035 to get your answer.
Sin 45° = opposite side / hypotenuse
1/2 = 8/h
h = 16
2)6/12 = 1/2
1/2 = sin 45°
6√3/12 = √3/2
√3/2 = cos 30°
Sum of angles of triangle = 180°
The 3rd angle = 180 - (45 + 30) = 180 - 75 = 105°
Angles = 30° , 45° , 105°