2 divides 20,22,24,26,28
3 divides 21,24,27
4 divides 20,24,28
5 divides 20,25
So, which number has not been listed above?
Between 20 and 28 students signed up for the chess club. The students could not be divided exactly into groups of 2, 3, 4, or 5. How many students signed up for the chess club?
4 answers
So our number should not be divisible by 2,3,4,or 5
that is, it can't be a multiple of of these numbers
So for the range of 20 - 28
multiples of 2: 20, 22, 24, 26, 28
multiples of 2: 21, 24, 27
multiples of 4: 20, 24, 28
multiples of 5: 20, 25
I don't see the prime number 29, so that's it
that is, it can't be a multiple of of these numbers
So for the range of 20 - 28
multiples of 2: 20, 22, 24, 26, 28
multiples of 2: 21, 24, 27
multiples of 4: 20, 24, 28
multiples of 5: 20, 25
I don't see the prime number 29, so that's it
Factor all numbers between 20 and 28.
20 = 2² ∙ 5
21 = 3 ∙ 7
22 = 2 ∙ 11
23 is a prime number
24 = 2³ ∙ 3
25 = 5²
26 = 2 ∙ 13
27 = 3³
28 = 2³ ∙ 7
The number 23 is the only number that can't be divided by 2, 3, 4, or 5.
23 students signed up for the chess club
20 = 2² ∙ 5
21 = 3 ∙ 7
22 = 2 ∙ 11
23 is a prime number
24 = 2³ ∙ 3
25 = 5²
26 = 2 ∙ 13
27 = 3³
28 = 2³ ∙ 7
The number 23 is the only number that can't be divided by 2, 3, 4, or 5.
23 students signed up for the chess club
good grief, how did I mess this one up, 29 is not even in the given range.
go with oobleck and bosnian,
it is obviously 23
go with oobleck and bosnian,
it is obviously 23