1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Klio2033 [76]
3 years ago
9

Some people think it is unlucky if the 13th day of month falls on a Friday. show that in that there year (non-leap or leap) ther

e will always be least such unlucky Friday but at one can be no more three.
Please answer ASAP
Mathematics
1 answer:
Vlad1618 [11]3 years ago
5 0
<span>There are several ways to do this problem. One of them is to realize that there's only 14 possible calendars for any year (a year may start on any of 7 days, and a year may be either a leap year, or a non-leap year. So 7*2 = 14 possible calendars for any year). And since there's only 14 different possibilities, it's quite easy to perform an exhaustive search to prove that any year has between 1 and 3 Friday the 13ths. Let's first deal with non-leap years. Initially, I'll determine what day of the week the 13th falls for each month for a year that starts on Sunday. Jan - Friday Feb - Monday Mar - Monday Apr - Thursday May - Saturday Jun - Tuesday Jul - Thursday Aug - Sunday Sep - Wednesday Oct - Friday Nov - Monday Dec - Wednesday Now let's count how many times for each weekday, the 13th falls there. Sunday - 1 Monday - 3 Tuesday - 1 Wednesday - 2 Thursday - 2 Friday - 2 Saturday - 1 The key thing to notice is that there is that the number of times the 13th falls upon a weekday is always in the range of 1 to 3 days. And if the non-leap year were to start on any other day of the week, the numbers would simply rotate to the next days. The above list is generated for a year where January 1st falls on a Sunday. If instead it were to fall on a Monday, then the value above for Sunday would be the value for Monday. The value above for Monday would be the value for Tuesday, etc. So we've handled all possible non-leap years. Let's do that again for a leap year starting on a Sunday. We get: Jan - Friday Feb - Monday Mar - Tuesday Apr - Friday May - Sunday Jun - Wednesday Jul - Friday Aug - Monday Sep - Thursday Oct - Saturday Nov - Tuesday Dec - Thursday And the weekday totals are: Sunday - 1 Monday - 2 Tuesday - 2 Wednesday - 1 Thursday - 2 Friday - 3 Saturday - 1 And once again, for every weekday, the total is between 1 and 3. And the same argument applies for every leap year. And since we've covered both leap and non-leap years. Then we've demonstrated that for every possible year, Friday the 13th will happen at least once, and no more than 3 times.</span>
You might be interested in
Please, I need to know how this question is done. please
oksian1 [2.3K]

subsitute x = 6 into the lengths

3(6) -7

18 - 7

11cm

(6) + 5

11cm

therefore it is a square when x = 6 because the sides are all equal

8 0
3 years ago
Which expression is equivalent to the expression below? Select all that apply.
katen-ka-za [31]

Answer:

2 and 3

Step-by-step explanation:

To simplify this expression, you will need to use the distributive property.

Multiply -2/5 by 15 = <u>- 6</u>, -2/5 by -20d = <u>8d</u>, and -2/5 by 5c = <u>-2c</u>.

you can switch these around to get -6 + 8d - 2c and -2c + 8d - 6.

Hope this helps :)

3 0
2 years ago
Nikki can make 5 free throws in 8 attempts. If she continues this pattern, how many free throws can she 128 attempts? Show your
konstantin123 [22]

Step-by-step explanation:

80 free throws on 128 attempts

8 0
2 years ago
. Kyle is 24 years older than his daughter Hannah. Kyle is 48 years old. How old is Hannah?
stealth61 [152]

Answer:

Hannah is 24years of age

4 0
2 years ago
Which are correct representations of the inequality...
KiRa [710]

Answer:

-6x+15

Step-by-step explanation:

-3(2x-5)

Distribute.

-6x+15

Add 5x and subtract 15 on both sides.

-6x-5x

-1x

Multiply -1 on both sides.

x>5

6 0
3 years ago
Other questions:
  • What does 4+9n mean
    6·1 answer
  • Im lost and I don’t understand what’s going on
    8·2 answers
  • What set of transitions are applied to parallelogram ABCD to create abcd?
    15·1 answer
  • The function h(t) = –16t2 + 28t + 500 represents the height of a rock t seconds after it is propelled by a slingshot. What does
    5·1 answer
  • How do you do proportions and simplify
    14·2 answers
  • The frequency table below shows the hourly wages of 22 factory workers. How many are paid $10.50 per hour or more? 1. The freque
    7·1 answer
  • William has $12.80 in coins to be deposited in the bank. There are 3 times as many quarters as nickels and 20 more dimes than ni
    8·1 answer
  • What does the line 2x-3y=7 look like
    15·1 answer
  • The speed of boat in still water is 15km/hr if needs 4 more his to travel 63 km against the current of a river than it needs to
    15·1 answer
  • 27 is 45% of what number?
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!