Find the remainder when 7 to the power 162 is divided by 800?

Asked by Last Modified  

1 Answer

Follow 3
Answer

Please enter your answer

Trainer

We will apply Remainder Theorem here. Remainder Theorem: Remainder of /P is x Remainder]/P e.g. Remainder of (34 x 36)/32 can be calculated as: Remainder -> 2 Remainder -> 4 so Remainder /32 -> Remainder /32 -> 8 Applying this theorem the current problem: (7^162)/800 can be visualized as...
read more
We will apply Remainder Theorem here. Remainder Theorem: Remainder of [M x N ]/P is [Remainder[M/P] x Remainder[N/P]]/P e.g. Remainder of (34 x 36)/32 can be calculated as: Remainder[34/32] -> 2 Remainder[36/32] -> 4 so Remainder [34 x 36]/32 -> Remainder [2 x 4]/32 -> 8 Applying this theorem the current problem: (7^162)/800 can be visualized as 7 x 7 x 7 x 7........162 times / 800 now, Remainder [7/800] -> 7 Remainder [7^2/800] -> 49 Remainder [7^3/800] -> 343 Remainder [7^4/800] -> Remainder [2401/800] -> 1 Now, when you see a Remainder of 1, your can now find a pattern. Remainders of the next powers of 7 will form a cycle of 7, 49, 343, 1, 7, 49. 343, 1........ This happens because, as per the Remainder Theorem, 7^5 can be written as 7^4 x 7 so Remainder[7^5/800] -> Remainder [(7^4 x 7)/800] ->Remainder[(1 x 7)/800] -> 7 And so on for 7^6, 7^7, 7^8........ Every time 7 has a power that is a multiple of 4, the remainder will be 1. 162 can be seen as (4*40) + 2 so Remainder [7^162/800] -> Remainder [(7^160) x (7^2)/800] -> Remainder [Remainder[(7^160)/800] x [Remainder[(7^2)/800]]/800-> Remainder [1 x 49]/800 -> So, Remainder will be 49 read less
Comments

Related Questions

What does Quantitative Aptitude teaches us?
I believe that aptitude is nothing but using our common sense. no need of any other skills.
Jayant
How do I increase my accuracy and speed in quantitative aptitude for SBI PO?
Keep your mind tension free. This helps in improving focus and accuracy. Speed of solving the problems can be improved with rigorous practice. Simple tricks can't be avoided.
Ashmita
0 0
6
What are the Best Books for preparing to IAS Preliminary?
NCERT Books with CSAT1 & CSAT2 by TMH
Chetan

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Related Lessons



CONCEPTUAL CLARITY
WHILE STUDYING ANY TOPIC MAKE SURE THAT AVOID MULTIPLE SOURCES. INSTEAD PICK UP ONE STANDARD SOURCE AND THE CONTENT OF WHICH YOU CAN COMPREHEND. READ IT MULTIPLE TIMES...FRAME A PICTURE IN MIND....ANALYSE...

Number systems
WE WILL LEARN HOW TO FIND THE NUMBER OF PRIME FACTORS IN A GIVEN NUMBER. 72=2^3*3^2.so total no of factors will be (3+1)(2+1)=12. Total no of factors =1+ no of prime factors + no of composite factors. So...
R

Ramakant Reddy

1 0
0

Looking for Quantitative Aptitude Coaching?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you