The area of a rectangle is 399 square feet. if the perimeter is 80 feet, find the length and width of the rectangle

The area of a rectangle is its length x width.

The perimeter of a rectangle is its length + length + width + width.

Let's have l stand for length and w for width.  A will stand for area and P for perimeter.  This gives us:

399 = l x w

80 = 2l + 2w  We can divide both sides of this equation by 2 to get 40 = l + w.

Now we need to find two numbers whose sum is 40 and product is 399.

Fitting some random numbers in gives us the numbers 19 and 21 for the length and width.

i dony know

step-by-step explanation:

1. sometimes

2.   never

3   .08c = 7.50+.05c   250 pages

step-by-step explanation:

1.   sometimes

the theoretical probability of rolling a 1 is 1/6.   perhaps you got really lucky and never rolled a 1   in those 60 times.   your experimental probability is 0.   or perhaps you rolled a 1   20 times.   your experimental probability is 20/60 is 1/3.     it really just depends on how you rolled in that experiment.

2.   never

the probability of the event occurring is 1.   that is being 100 % sure it will happen.   that is the maximum amount of confidence we have.

3.   no customer card cost:   .08 times number of pages

customer card cost:   7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250  

the cost is the same at 250 pages