160,000 - 40,000= 120,000/4 = 3 sets of new tires in the first year and 4 every consecutive year.
Let’s look at the permutations of the letters “ABC.” We can write the letters in any of the following ways:
ABC
ACB
BAC
BCA
CBA
CAB
Since there are 3 choices for the first spot, two for the next and 1 for the last we end up with (3)(2)(1) = 6 permutations. Using the symbolism of permutations we have:

. Note that the first 3 should also be small and low like the second one but I couldn’t get that to look right.
Now let’s see how this changes if the letters are AAB. Since the two As are identical, we end up with fewer permutations.
AAB
ABA
BAA
To make the point a bit better let’s think of one A are regular and one as bold
A.
ABA and AB
A look different now because we used bold for one of the As but if we don’t do this we see that these are actual the same. If they represented a word they would be the same exact word.
So in this case the formula would be

. We use 2! In the denominator because there are 2 repeating letters. If there were three we would use 3!
Hopefully, this is enough to let you see that the answer is A. The number of permutations is limited by the number of items that are identical.
With the sum of 99, we will get 50 pairs whole numbers. Why?
Let’s start with
0+ 99
1 + 98
2 + 97
3 + 96
4 + 95
5 + 94
6 + 93
7 + 92
8 + 91
9 + 90
10 + 89
………
……..
43 + 49
44 + 50
Therefore, if you’re going to count all pairs of whole number, you will get 50 pairs of whole number with the sum of 99.
Hope this helps!
Answer:
[895.05; 940.81]kWh
Step-by-step explanation:
Hello!
Be X: monthly electricity usage by a residential customer
X~N
σ²: 12100KWh²
To estimate the population mean using a 98% CI you have to use the following formula
[X[bar]±
*
]
1-α: 0.98
α0.02
α/2: 0.01
1-α/2:0.99

n= 125
X[bar]= ∑X/n= 228565/125= 917.93
[917.93±2.326 *
]
[895.05; 940.81]
Using a 98% confidence level you'd expect that the interval [895.05; 940.81]kWh will include the average monthly electricity usage of residential customers.
I hope this helps!
Raw data:
Electric Usage
765
1139
714
687
1027
1109
749
799
911
631
975
717
1232
806
637
894
856
896
1272
1224
621
606
898
723
817
746
933
595
851
1027
770
685
750
1198
975
678
1050
886
826
1176
583
841
1188
692
733
791
584
1163
593
1234
603
1044
1233
1178
598
904
778
693
590
845
893
1028
975
788
1240
1253
854
1185
1164
741
1058
1053
795
1198
1240
1140
959
938
1008
1035
1085
1100
680
1006
977
1042
1252
943
1165
1014
912
791
612
935
864
953
667
1005
1063
1095
1086
810
1032
970
1099
1229
892
1074
579
754
1007
1116
583
763
1231
966
962
1132
738
1033
697
891
840
725
1031