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When 33333^{333} is divide by 11, the remainder is

Solution

✅ Correct Option: 4

You can find the cyclicity easily (use the calculator if available):

PowerDivisionQuotient + Remainder

313^1

3÷113 \div 11

00 remainder 33

323^2

9÷119 \div 11

00 remainder 99

333^3

27÷1127 \div 11

22 remainder 55

343^4

81÷1181 \div 11

77 remainder 44

353^5

243÷11243 \div 11

2222 remainder 11

363^6

729÷11729 \div 11

6666 remainder 33

373^7

2187÷112187 \div 11

198198 remainder 99

The cycle repeats every 5 powers: 3, 9, 5, 4, 1.

This means that we can find the general form for every 3x3^x divided by 11.

We know that x=333x=333 in this case. Hence, breaking 33333^{333} in the general form will allow us to map it to the remainder.

General Form (k∈W)(k \in \text{W})ExampleRemainder
35k+13^{5k+1}313^133
35k+23^{5k+2}323^299
35k+33^{5k+3}333^355
35k+43^{5k+4}343^444
35k3^{5k}353^511

We need to find where 333333 fits in the cycle of 55 (i.e. find the highest multiple of 55 before 333333):

Since multiples of 55 end in 00 or 55, we can break down 333=330+3333 = 330 + 3.

⇒333=5k+3\Rightarrow 333 = 5k + 3

(where kk is a whole number and 5k=3305k=330)


Hence, 3333=35k+33^{333} = 3^{5k + 3}

From the table, we see the remainder at 35k+33^{5k + 3} is 5\boxed{5}

It means that the remainder of 33333^{333} is the same as 333^3. You can use this pattern-finding approach (cyclicity) for any numbers!

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