A) The first step needs 100 bricks, the second needs 98, the third needs 96, and so on. Therefore the number of bricks for the nth step is: a_n = a_1 + d(n-1), where a_1 = 100 (the first term), d = -2 (difference).
a_n = 100 - 2(n-1) = 102 - 2n, and for the 30th step, a_30 = 102 - 2*30 = 42. So the top step will need 42 bricks.
b) The total staircase will need: 100 + 98 + 96 + ... + 44 + 42, and there are n = 30 terms. Using the formula for the sum of an arithmetic sequence:
S = (a_1 + a_n)*n/2 = (100 + 42)*30/2 = 2130
Therefore, 2130 bricks are required to build the entire staircase.
Answer:
<u>A</u>
Step-by-step explanation:
<u>Given</u>
<u>Solving</u>
- Take the square root on both sides
- √x² = √9/4
- ⇒ x = 3/2
- <u>Option A is the correct option.</u>
The answer would be D Graph b.
Answer:
5/16
Step-by-step explanation:
As you can see in the 16 given possible outcomes, in 5 of them at least 3 coins land facing up. Since there are 16 outcomes in total, the probability that at least three coins land facing up is 5/16. Hope this helps!
Answer:
The first set of ordered pairs is a function, because no two ordered pairs have the same first coordinates with different second coordinates. The second example is not a function, because it contains the ordered pairs (1,2) and (1,5). These have the same first coordinate and different second coordinates.
