when the integer n is divided by 8, the remainder is 3. what is the remainder if 6n is divided by 8?
The remainder is 2.
Quick Scoop: What’s Going On?
You’re told:
- When the integer nnn is divided by 8, the remainder is 3.
That means nnn can be written as
n=8k+3n=8k+3n=8k+3
for some integer kkk.
You’re asked:
- What is the remainder when 6n6n6n is divided by 8?
Step-by-step Reasoning
- Start with the expression for nnn:
n=8k+3n=8k+3n=8k+3
- Multiply both sides by 6 to get 6n6n6n:
6n=6(8k+3)=48k+186n=6(8k+3)=48k+186n=6(8k+3)=48k+18
- Now look at 48k+1848k+1848k+18 modulo 8:
-
48k48k48k is clearly divisible by 8, since 48=8×648=8\times 648=8×6.
So 48k48k48k leaves remainder 0 when divided by 8. -
Focus on 18:
-
18=16+2=8×2+218=16+2=8\times 2+218=16+2=8×2+2
so 18 leaves remainder 2 when divided by 8.
- Put it together:
- 48k48k48k contributes remainder 0,
- 18 contributes remainder 2,
so 6n=48k+186n=48k+186n=48k+18 leaves remainder 2 when divided by 8.
Therefore, the remainder is 2.
Tiny Story to Remember It
Think of numbers that give remainder 3 when divided by 8:
3, 11, 19, 27, … Pick one, say n=11n=11n=11:
- 6n=6×11=666n=6\times 11=666n=6×11=66
- Divide 66 by 8:
8×8=648\times 8=648×8=64, remainder 66−64=266-64=266−64=2.
Same remainder: 2. ✅ Answer: The remainder when 6n6n6n is divided by 8 is 2.