Gareth 30 students in a class and the ratio of boys to girls in the class is 2:3 calculate the number of goals
1 answer:
Answer:
<em>There are 12 boys and 18 girls</em>
Step-by-step explanation:
<u>Equations</u>
There are 30 students in a class. Let's call:
x = number of boys
Since the sum of boys and girls is 30:
30 - x = number of girls
The ratio of boys to girls is 2:3, thus:
Crossing denominators:
3x = 2(30 - x)
Operating the parentheses:
3x = 60 - 2x
Adding 2x:
5x = 60
Dividing by 5:
x = 60/5 = 12
x = 12
There are 12 boys and 30-12=18 girls
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We factor the denominators
Factor x^2 - 16
x^2 - 4^2
We use a^2 - b^2 = (a+b)(a-b)
so x^2 - 4^2 = (x+4)(x-4)
Replace it in the given equation
Excluded values are the values that makes the denominator 0
we have (x-4) and (x+4) in the denominator
We set the denominator =0 and solve for x
x-4 =0
Add 4 on both sides
x= 4
x+4=0
subtract 4 onboth side
so x= -4
Excluded values are x=-4 and x=4
We have
In order to obtain easily the table, we need to clear y
then we evaluate for values of x
if x=0
y=-4(0)+1=1
y=1
if x=1
y=-4(1)+1=-3
y=3
if x=2
y=-4(2)+1=-7
y=-7
if x=3
y=-4(3)+1=-11
y=-11
So the table for the given equation is
x y
0 1
1 -3
2 -7
3 -11