Answer:
20 students
Step-by-step explanation:
If the class decreased by 15%, the students that she has now (17) represents a percentaje of:
100% - 15% = 85%
so<u> the 17 students are 85% of what she had</u>:
Students Percentage
17 ⇒ 85%
and we are looking for how many students she had 2 years ago, thus we are looking for the <u>100%</u> of students (the original number of studens). If we represent this number by x:
Students Percentage
17 ⇒ 85%
x ⇒ 100%
and we solve this problem using the <u>rule of three</u>: multiply the cross quantities on the table( 17 and 100) and then divide by the remaining amount (85):
x = 17*100/85
x = 1700/85
x=20
2 years ago she had 20 students
The airplane flies at 260 mi/h with no wind, while the rate of the wind is 60 mi/h.
<h3>What is an
equation?</h3>
An equation is an expression that shows the relationship between two or more numbers and variables.
Let a represent the rate of the airplane with no wind. and b the rate of the wind, hence:
(a - b)3.2 = 640
a - b = 200 (1)
Also:
(a + b)2 = 640
a + b = 320 (2)
The solution to equation 1 and 2 is:
a = 260, b = 60
The airplane flies at 260 mi/h with no wind, while the rate of the wind is 60 mi/h.
Find out more on equation at: brainly.com/question/2972832
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80. there's no mathematical equations, also there's nothing to compare
Tabitha Tidbits costs $7 per bag, and Figaro Flakes is $5.50 per bag.
You need to set up a system of equations. Use "x" for Tabitha Tidbits and "y" for Figaro Flakes, and let the total cost of each trip equal c. Using the equation ax+by=c, substitute the cost of each trip in for c, and the number of bags for each food for a and b respectively. The two equations will be:
3x+4y=43
3x+6y=54
Isolate x in the first equation and you will get:
x=(43-4y)/3
Substitute the above equation for x into the other equation:
3*((43-4y)/3)+6y=54
Isolate y in this equation, and you will get 11/2, which is 5.5
So the cost of one bag of Figaro Flakes is $5.50
Now substitute this into the equation where you isolated x:
(43-4(5.5))/3
You will get x=7, so a bag of Tabitha Tidbits is $7
