1 1
2 3
3 6
4 10
5 15
6 21
7 28
8 36
9 45
10 55
11 66
12 78
13 91
14 105
15 120
16 136
17 153
18 171
19 190
20 210
21 231
22 253
23 276
24 300
here is a spreadsheet to help you understand the stair problem notice for 1 step 1 block, 2 step, 3 block, 3 step, 6 block and so on notice the blocks for the number of a step is that step plus all the other blocks needed to make all the one(s) below it. Notice it takes 105 blocks to make 14 steps.
So if you are familiar with the summation process you would add the number that go with that stair with all the stairs below it. example step 5 blocks would be 5 + 4 + 3 + 2 +1 or 15 blocks. I hope this gets you started. The second part I do not understand the problems because they are not equations. NO equal signs
glad if it helps
<h2>
Answer with explanation:</h2>
Given : An urn contains 2 red marbles and 3 blue marbles.
Total marbles = 2+3=5
a) The general ways in which the person could get a red marble and a blue marble are :
1) He draws red marble first and then second marble as blue.
2) He draws blue marble first marble and then second marble as red.
b) The number of ways to get one red and one blue marble is given by :-
(i)
c) Number of ways to get 2 marbles from 5 is given by :-
(ii)
Now, The probability the person gets a red and a blue marble will be :-
[Divide (i) by (ii)]
Hence, the probability the person gets a red and a blue marble= 0.6
Answer:
Margin of error at 90% is 0.024
Margin of error at 99% is 0.037
Step-by-step explanation:
Sample size = 1076
A poll found that 64% of a random sample of 1076 adults said they believe in ghosts.
So, No. of adults said they believe ghosts = 
So, x = 688
n = 1076




z at 90% confidence is 1.64


So, margin of error at 90% is 0.024
Find the margin of error needed to be 99% confident.
z at 99% confidence is 2.58


So, margin of error at 99% is 0.037
Answer:
The anwerss to the question are
(A) P(No less than two people use their phones while driving) = 0.1225
(B) P(The probability that no more than one person of the three people use their cell phone while driving) = 0.147875
Step-by-step explanation:
The given relations are
Percentage of motorists that routinely drive while sing their phone = 35 %
The probaboloty that if a peerson is random;ty selected from a group of hudred person routinely uses their phone wjile friving P(phone) = 35
The probability that a motorist randomly selected fron a set of 100 do not routinely use thir phones while driving = P(No celll phone) = 65
Then the probability that when three people are selected at random at least two people of the three people use their cell phone while driving is
P(phone) = 35/100m = 0.35
P(No celll phone) = 65/100 = 0.65
(A) Probability of at least two of three use their phones whle driving is
0.35×0.35×0.65 +0.35×0.35×0.35 = 0.1225
(B) The probability of only one person out of three seted use their phones while driving is
(0.35)(0.65)(0.65) = 0.147875
Answer:

Step-by-step explanation:
we know that
---> by addition angle postulate
we have
----> given problem
----> given problem
substitute in the expression above

Divide by 2 both sides
