When a certain number is divided by 4, the remainder is 3. If twice that number is divided by 4, what is the remainder?

The number is 4n+3 where n is a whole number

if we double it, then we get 8n+6

if we divide it by 4 we get

(8n+6) / 4 = (8n/4) + (6/4) = 2n+1+2/4

the remainder is 2 because it didn't divide into the 4