Remainder

we can rewrite the given info as following:

n=3x+2 and t=5y+3

to find the remainder when nt is divided by 15:

statement (1): n-2 is divisible by 5
3x+2-2=3x is divisible by 5, which means x is divisible by 5. so, 3x is divisible by 15, with the remainder "0".
when divided by 15, nt will have a remainder "0".

SUFFICIENT

Statement (2): t is divisible by 3

5y+3 is divisible by 3....5y is divisible by 3, which means 5y+3 is divisible by 15 with the remainder 3.
Since n is divided by 3 with the remainder 2, when multiplied by t, it doesn't give precise answer, so insufficient.

So, the OA is A

correct?

n=3a+2
t=5b+3

St 1) n-2 = 5x ; we know that n-2 =3a so n-2=15t and n = 15t+2

no information on t - insuf

St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3

no info on n - insuf

ST 1+2)
(15t+2) (15m+3) / 15

Remainder: 2x3 = 6

Hence, C

Logitech- How did u get this? What is the significance of 6?
(15t+2) (15m+3) / 6

Tryingmybest wrote:Logitech- How did u get this? What is the significance of 6?
(15t+2) (15m+3) / 6

Sorry It was a typo. I was thinking of the result I edited my post

Big Brother is watching u

Just kidding.. Wonderful solution.

Tryingmybest wrote:Big Brother is watching u

I appreciate that. And also I want to thank moneyman for all of these great official questions.

And I know his test is very soon. GOOD LUCK man!

Logitech -Sorry to bug u again

St 2) t=5b+3 ; t=3y ..5b+3 = 3y ...5b=3(y-1) and t = 15m + 3

If 5b=3(y-1) => t = 3(y-1)+3 how did u get t = 15m + 3??

Please enlighten me.

5b=3(y-1) well since 5b is also a multiple of 3

LCM(3:5) = 15

so for example

5x3 = 3 (6-1)

So this actually tells us 5b has 3 as a factor.

and t = 15m + 3

Did I confuse you even more ?

Or in other words can I say

5b is a multiple of 3 => b must be a multiple of 3
=> 5b will be of the series 15,30,45 etc
=> 15 m (where m must be a multiple of 3)

It makes perfect sense now.. Thanks!!

Test is tomorrow..Thanks Logitech

I will pray for you. You have been working hard. Go and claim what is yours.

Shall the force be with you!

Thanks bro..appreciate it