Question

OMG THIS ONE IS WAY HARDER (i think)

Which number supports the given conjecture?

If the sum of the digits of a number is divisible by 9, then the number is also divisible by 9.

A.
19

B.
54

C.
87

D.
109

Answer 1

@Demonx341 i kinda new the last one but this one is killing me

Answer 2

add up the digits of last option, what do u get ?

Answer 3

its not conjecture :O its already proven *tears* T_T

Answer 4

ill let them help you :P

Answer 5

im in k12

Answer 6

hey gane, r u good at adverb sith grade questions? im really confused

Answer 7

math theorems start out their lives as conjectures

Answer 8

it is a lol???

Answer 9

so did you add the digits of each number? and then divide by 9

Answer 10

but it said divide by nine twice

Answer 11

a) 1 + 9 = 10 , and 10 is not divisible by 9

Answer 12

but its the same for d

Answer 13

a and d have the same answer

Answer 14

are they divisible by 9 ?

Answer 15

no

Answer 16

the question is kind of ambiguous, indirectly all 4 statements support the conjecture

Answer 17

since the conjecture is true

Answer 18

that must be a stupid question to ask right after you saying they have same answer :O

Answer 19

right..

Answer 20

see what i mean

Answer 21

but i think they want the positive conjecture (not the contrapositive)

Answer 22

which of these is evidence of the positive conjecture .

Answer 23

whutt :O

Answer 24

strike off options a and d
focus on options b and c

Answer 25

i didn't learn that i don't think

Answer 26

ok

Answer 27

addup digits for number in option b,
wat do u get ?

Answer 28

12

Answer 29

which of these numbers is evidence for the claim :
"if the sum of the digits of a number are divisible by 9, then the number is divisible by 9"

Answer 30

c?

Answer 31

so first you need to satisfy the hypothesis of that claim.

Answer 32

how on earth 5 and 4 add up to 12 ?

Answer 33

nope,

Answer 34

oops i thought it said 5 and 7

Answer 35

8 + 7 is not divisible by 9

Answer 36

9

Answer 37

is 9 divisible by 9 ?

Answer 38

so b

Answer 39

you should be confident its b)

Answer 40

i feel dumb + stupid = idiot = me

Answer 41

no, its just 'different' way of reading

Answer 42

hehe yeah its only a conjecture dont need to think of the opposite :)

Answer 43

or dumb + stupid + idiot = me XD that was easy and i did everthing wrong

Answer 44

how did u get dumb + stupid = idiot

Answer 45

everythng*

Answer 46

@MCLover1477 same here :3

Answer 47

a) and d) are evidence of the contrapositive version of the conjecture

Answer 48

the idiot must be stupid and dumb, i see you're from all those. keep up the good work :)

Answer 49

there is no contrapositive in conjecturs :D

Answer 50

a) c) d) are evidence of the contrapositive form of the conjecture.

b) is evidence of the conjecture

Answer 51

sure, you can make a contrapositive form of a conjecture

Answer 52

lol @ganeshie8

Answer 53

i can make , but u dont need to consider it xD

Answer 54

if you prove the contrapositive form of the conjecture, that is equivalent to proving the original conjecture

Answer 55

but this is where you have to guess what the teacher had in mind :)

Answer 56

who is from k12 btw?

Answer 57

nvm...

Answer 58

Me

Answer 59

since there is only one answer to the question, that kind of narrows it down

Answer 60

what?

Answer 61

@ikram002p

Answer 62

what?

Answer 63

contrapositive follows the truth value of the given conditional, so yeah we can use examples that satisfy contrapositive

Answer 64

here is the contrapositive :
If a number is not divisible by 9, then the sum of the digits of the number is not divisible by 9.

Answer 65

as long as you're not introduced to logic, your teacher is safe in giving ambiguous options

Answer 66

in other words, because you're not going to find an instance where the conjecture is false, since your conjecture is a theorem, every number is evidence of your conjecture

Answer 67

this is not the contrapositive xD
its if the sum of digits of a number is not divisible by 9 then the number is not divisible by 9

Answer 68

take for example conjecture:

every number is a product of primes.

evidence 4 = 2 x 2 , and 2 , 2 are primes

Answer 69

that would be called negation ikram

Answer 70

every positive integer, except 1

Answer 71

4=4*1 so what xD

Answer 72

also called inverse

Answer 73

statement : if a, then b
inverse : if NOT a, then NOT b
converse : if b, then a
contrapositive : if NOT b, then NOT a

Answer 74

anyways, i agree that given the context of the question (level, etc) , it should be b)

Answer 75

what im i wrong :O how

Answer 76

my point was that a), b) , c) and d) all support the conjecture, some indirectly

Answer 77

you're right in saying that below is not contrapositive

its if the sum of digits of a number is not divisible by 9 then the number is not divisible by 9

Answer 78

here is the contrapositive :
If a number is not divisible by 9, then the sum of the digits of the number is not divisible by 9.

Answer 79

your point is valid

Answer 80

so there is nothing more to say about that?

Answer 81

when a conjecture is a theorem, you won't be able to find any counter examples

Answer 82

lol nvm i have some reading problems xD

Answer 83

so the question itself should not exist

Answer 84

right, that was my point

Answer 85

so every number is evidence of a conjecture (a general conjecture about all numbers)

Answer 86

if its a theorem

Answer 87

yes i was kindof torn between being strictly correct versus helping the OP

Answer 88

hehe that makes a problem to me , like which is more important

Answer 89

but i think when you do math, you find conjectures usually in a direct way

Answer 90

most people search for positive theorems, not negations of conjectures

Answer 91

thats debatable

Answer 92

one more of conjecture in this post xD

Answer 93

yes that might be a conjecture about conjectures

Answer 94

`most people search for positive theorems, not negations of conjectures `

is a statistics survey question, not a conjecture ikram ;p

Answer 95

at least maybe at the basic level, when we start out doing math. we find positive patterns, patterns that numbers do have, rather than what they do not. but yes its debateable

Answer 96

we notice things like numbers are even , and are prime (not as quickly what they are not )

Answer 97

positive qualities