21 students because if 6 represents 30% u add 6 two more time which equals 18 and 90% then u add 3 more because it is half of 6. when u add 3 more u will get 21 and 100%
Remark
There is no short way to do this problem and no obvious way to get the answer other that to solve each part.
Solve
A
Multiply by 2
x + 1.6 = 2(x + 0.1) Remove the brackets
x + 1.6 = 2x + 0.1*2
x + 1.6 = 2x + 0.2 Subtract x from both sides
1.6 = x + 0.2 Subtract 0.2 from both sides
1.6 - 0.2 = x
1.4 = x
Circle A
B
Subtract 2x from both sides.
3x - 2x = 1.4
Circle B
C
Remove the brackets.
4x + 6 = 2x - 6 Add 6 to both sides
4x + 12 = 2x Subtract 4x from both sides.
12 = -2x Divide by - 2
12/-2 = x
x = - 6 Don't circle C
D
I'm going to be very scant in my solution of this. You can fill in the steps.
3x = 4.2
x = 4.2/3
x = 1.4
Circle D
Answer: there is only one solution
Step-by-step explanation:
Combine like terms by performing the opposite operation of subtracting 4x on both sides of the equation
The 4x's will cross out on the right
4x - 4x = 0x = 0
On the left:
2x - 4x = -2x
Now the equation looks like:
-2x + 3 = 2
Continue to combine like terms by subtracting 3 on both sides of the equation
On the left:
3 - 3 = 0
On the right:
2 - 3 = -1
Equation:
-2x = -1
Isolate x by performing the opposite operation of dividing -2 on both sides of the equation
On the left:
-2x ÷ -2 = 1
On the right:
-1 ÷ -2 = 1/2
x= 1/2
$12 per foot, 618.79 feet total.
Multiply 618.79 by $12 to get the answer: $7,425.48