Question

Flag question
What will be the unit's digit of (787)^102!?
Select one:
a. 1
b.3
C. 5
d. 6​

Answer 1

Answer:

Flag question

What will be the unit's digit of (787)^102!?

Select one:

a. 1

b.3

C. 5

d. 6

Answer 2

Answer:

9 is the unit digit of $(787)^{102}$

Step-by-step explanation:

Explanation :

Given , $(787)^{102}$

So , last digit og 787 is 7

Step1:

Now , $7^{1}$ = 7 where 7 is the unit digit

$7^{2} = 49$ ⇒ 9 is the unit digit of 49

$7^{3} = 343$ ⇒3 is the unit digit of 343

$7^{4}$ = 2,401 ⇒ 1is the unit digit of 2,401

$7^{5}$ = 16,807 ⇒7 is the unit digit of 16,807

So the cyclicity of 7 is nothing but 4

Step2:

On dividing 102 by 4 we get 2 as a remainder .

We have l = 7 and r = 2

where l is last digit number and r is remainder

So ,we have $l^{r}$ = $7^{2}$ = 49

⇒ 9 is the unit digit of 49 .

Final answer :

Hence , the unit digit of $(787)^{102}$ is 9