Let x be the cost of each book.
So, the cost of 4 books is 4x.
For the purchase of 4 books, he got a discount of $20.
So, the amount he paid for the first four books = 4x - 20.
Now, the cost of 5 books is 5x.
For the purchase of 5 books, he got another discount of $5.
So, the amount he paid for the five books = 5x - 5.
Total money spent = $87.
Therefore, (4x - 20) + (5x - 5) = 87
4x + 5x - 20 - 5 = 87
9x - 25 = 87
9x = 87 + 25
9x = 112
Divide both sides by 9.
x = 12.4
Hence, the cost of each book = $12.4.
To start, first let us define our variable, since it is what we are going to use to solve this. x will equal the width of the table, and since the length is 4 times as long as the width, it will be represented as 4x. Now that we have our dimensions, we can multiply 4x and x (our dimensions) to get the area which is 4x^2. Then, since the problem states that the area is 100, you would set 4x^2 equal to 100 which would look like this: 4x^2=100. Then, you solve for x, starting by dividing both sides by 4. This would result in this: x^2=25. Finally, to find the width or x, you square root both sides and you get x=5. Now, to find the length, multiply the width by 4. As your answer, you get that 20 is the length, and 5 is the width.
Answer:
0.5
Step-by-step explanation:
sjsbdir rievrjrvrjrbrhdbdjdbekebejebsjsbsirvrirvrjrrhirvrjrbrjr dry it said it had to be 20 characters long
Step-by-step explanation:
1. The first step has 1 block. The second step has 2 blocks. The third step has 3 blocks. So the nth step needs n blocks.
2. A staircase with n steps has 1 + 2 + 3 + ... + n steps. This is an arithmetic sequence where the first term is 1 and the last term is n. The sum of the first n terms is:
y = n/2 (1 + n)
3. Solve for n.
2y = n (1 + n)
2y = n² + n
0 = n² + n − 2y
Using quadratic formula:
n = [ -1 ± √(1 − 4(1)(-2y)) ] / 2
n = [ -1 + √(1 + 8y) ] / 2