Number System - Questions & Discussions

hello everybody,
please explain this one for me.

Q: find the remainder when 3^5^9^13^.....33 is divided by 5??

(A) 1
(B)2
(C)3
(D)4
(E)0

hello everybody,
please explain this one for me.

Q: find the remainder when 3^5^9^13^.....33 is divided by 5??

(A) 1
(B)2
(C)3
(D)4
(E)0


should be 3 ..

3^(4k + 1) ends in 3 ..
hello everybody,
please explain this one for me.

Q: find the remainder when 3^5^9^13^.....33 is divided by 5??

(A) 1
(B)2
(C)3
(D)4
(E)0

Try to first express this in the form 4k+1
5^9^13^.....33/4
=>1
=>5^9^13^.....33/4 = 4K+1
3^4k+1/5
=>(3^4k/5) x 3/5
=>1x3
=>3

yeah answer to is correct but i cudn;t understand after step
=>(3^4k/5)x3/5
=>1x3
=>3.....

yeah answer to is correct but i cudn;t understand after step
=>(3^4k/5)x3/5
=>1x3
=>3.....


for this remember the cyclicity

3^1=3
3^2=9
3^3=27
3^4=81
3^5=243

3,9,7,1...so any number of form 3^4k will have unit digit 1..and now on dividing by 5 it gives 1 as remainder

so 1x3/5
=3

thanx alot...got it....:)

hi,

Q: N! is completely divisible by a 13^52.what is the sum of digits of smallest such number N?
a.11
b.15
c.16
d.19


regards
-abiral

hi,

Q: N! is completely divisible by a 13^52.what is the sum of digits of smallest such number N?
a.11
b.15
c.16
d.19


regards
-abiral


is the answer 15?
hi,

Q: N! is completely divisible by a 13^52.what is the sum of digits of smallest such number N?
a.11
b.15
c.16
d.19


regards
-abiral

is the answer is 16?

answer is 16...:)

abiral3081 Says
answer is 16...:)


please explain the approach as well... thanks

Q: N! is completely divisible by a 13^52.what is the sum of digits of smallest such number N?
a.11
b.15
c.16
d.19

Solution: N! = 1 * 2 * 3 * .... 13 *... 26 * ... 39 *...* N

In this series of numbers, we need to consider only the multiples of 13.

Most of these multiples have only 13^1 as the factor and not higher powers of 13 like (13^2 or 13^3 as its factor).

But we also need to note that several numbers such as:
169 = 13 * 13; 338 = 2 * 13 * 13; 507 = 3 * 13 * 13 = 39 * 13.
Thus, all these numbers contain 2 powers of 13 or in other words, divisible by 13^2.

So in 507!, we have 39 + 3 = 42 powers of 13 (Since the 3 numbers above contain 2 powers of 13 instead of just 1).

But N! should be divisible by 13^52, hence we need to extend the value of N to include 10 more multiples of 13, thus N needs to be 10 multiples of 13 more than 507 = 507 + 130 = 637.

Then, we can be sure that N! = 637! contains 52 powers of 13 or in other words, 637! is exactly divisible by 13^52.
Sum of digits of N = 6 + 3 + 7 = 16, which is the final answer.

Cheers,
Raj Narap.

Answer :c

find the remainder when (38^16!)^1777 is divided by 17

a. 1
b. 16
c. 8
d. 13

Answer:a

find the remainder when (38^16!)^1777 is divided by 17

a. 1
b. 16
c. 8
d. 13

Answer:a


here u can express 16!^1777 as 4k

=>38^4k/17
=>1
find the remainder when (38^16!)^1777 is divided by 17

a. 1
b. 16
c. 8
d. 13

Answer:a


As, 38 and 17 are co-prime, and the Euler number of 17 is 16, any power of 38 which is a multiple of 16 will give remainder equal to 1.

So, option (a)

The equation 4x-Ay=B has a number of integral soln.If HCF of (A and 4) is 1 and the number of solution (x,y)for 0Puys the answer is 1. A=11 ...Please post ur approach ...

Some Specifications of a password
a) 7 digit odd no.
b) 1st 2 digits = 16 or 18 ;
c) 6 occurs twice ; 8 occurs once .
Max trials to crack such password =

a) 7680
b) 1250
c) 3840
d) 5760

Success ....
its 5760 😃

The equation 4x-Ay=B has a number of integral soln.If HCF of (A and 4) is 1 and the number of solution (x,y)for 0Puys the answer is 1. A=11 ...Please post ur approach ...


We can see value of x will increase by 11 and y by 4

so , last term = 11 + (45 - 1 ) 11 = 495
11 would be the answer here !!
now u'll say y did i choose 11 . well star from 5 , 7 , 9, 11 as these are smalles no's coprime to 4 . 11 will satisfy your no. of solutions.

Suja