Question

find a value of n that makes the expression divisible by 2, 3, 5 (18n)

Answer 1

what is the question exactly? finding a value of n that makes 18n divisible by 2, 3, and 5?

Answer 2

if you prime factor 18, you get:\[2\cdot3^2\]
you are missing a 5. so if n =5 you are good.

18(5)=90

and 90 is divisible by 2, 3, and 5.

Answer 3

ok thanks so how about n+7

Answer 4

making n+7 divisible by 2, 3, and 5?

Answer 5

yes

Answer 6

Do you know modular arithmetic at all? that would make this loads easier.

Answer 7

no

Answer 8

only 10 dont know what that is

Answer 9

hmm...well it might be a little hard to explain then. First, we need to note that if a number is divisible by 2, 3 and 5, then it is divisible by 30.

So we want n+7 to be a multiple of 30.

In mathematical speak, that means:
\[n+7=30k\]

where k is some integer.

Solving for n gives:
\[n=30k-7\]

That is the condition that needs to be met for n+7 to be divisible by 30.

Answer 10

huh!!!

Answer 11

thanks for ur help