Binomial Theorem Question 17

Question 17 - 31 January - Shift 1

The remainder on dividing $5^{99}$ by 11 is_______________

Show Answer

Answer: 9

Solution:

Formula: Divisibility concept

$5^{99}=5^{4} .5^{95}$

$=625[5^{5}]^{19}$

$=625[3125]^{19}$

$=625[3124+1]^{19}$

$=625[11 k \times 19+1]$

$=625 \times 11 k \times 19+625$

$=11 k_1+616+9$

$=11(k_2)+9$