Step-by-step explanation:
1.)20x + 100 = 1440
-Let the number of couples be x. So, the total amount paid by all the couple’s are $20x. School paid $100 as security, so the total amount paid is
$ (20x + 100)
2.) 20x = 1440 - 100 ⇒ 20x = 1040
X = 52
3. ) The security money is $100, so the couples paid $1440- 100 = $1040 in total. As the couples paid $ 20 each than- 
= 52
Remark
Start by figuring this out for 1 car. Worry about the 7 part when you find 1.
This problem is used quite frequently in physics. For example resistors in parallel use the same equation.
Formula
1/frank + 1/carla + 1/missy = 1/ time taken to do 1 mar.
Givens
Frank = 2 hours
Carla = 2 hours
Missy = 3 hours.
Substitute and Solve
1/2 + 1/2 + 1/3 = 1/Three_together.
3/6 + 3/6 + 2/6 = 1/Three_together.
8/6 = 1/Three_together. Cross multiply
8 * Three_Together = 6*1
8 * Three_Together = 6 Divide by 8
Three_Together = 6/8 = 3/4 = 0.75 hours. or 45 minutes for 1 car
Seven Cars
For 7 cars multiply 0.75 by 7
7 * 0.75 = 5.25 hours. <<<< Answer
Answer:
a
Step-by-step explanation:
Answer:
C
Step-by-step explanation:
4x+3y=-24
eq. of any line perpendicular to given line is
3x-4y=a
4y=3x-a
y=3/4x -a/4
where a is an arbitrary constant.
The figure is not a parallelogram
good luck
