If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7^m+7ⁿ is divisible by 5 is?

Answer is given as 1/5

Plz explain

Question

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7 m +7 n is divisible by 5 is? Answer is given as 1/5 Plz explain

SAGAR SINGH - IIT DELHI · Answer

Dear student,

If a number is divisible by 5 - it should either end at 0 or 5

the possible values last digit of 7^m is = 7,9,3,1

one can select two numbers from it in = 6 ways

2 favourable conditions are = 7,3 and 9,1

Probability =1/3

Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar respectively : Click here to download the toolbar..

Askiitians Expert
Sagar Singh
B.Tech, IIT Delhi

Akanksha R.S · Answer

The answer is 1/5. The total possibilities are....(7,3), (7,9), (7,1), (3,9),(3,1),(9,1),(7,7),(9,9),(3,3),(1,1).......

Among these oly (7,3) and (9,1) satisfy the condition.....so we can take the probability as 2/10 ie 1/5

Vineet · Answer

I guess it will be 1/4 .Cases are (7,7)(7,9)(9,7)(7,3)(3,7)..............(1,1)total cases are 16 and favourable cases are 4 . so it`s 1/4

Thank you for registering.

Register Now and Win Upto 25% Scholorship for a Full Academic Year !

Enter Your Details

Registration done!

Guest

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7 m +7 n is divisible by 5 is? Answer is given as 1/5 Plz explain

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7^m+7ⁿ is divisible by 5 is?

Answer is given as 1/5

Plz explain

3 Answers

Think You Can Provide A Better Answer ?

Other Related Questions on Magical Mathematics[Interesting Approach]

ASK QUESTION

Answer and earn gift vouchers

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Complete Self Study Package designed by Industry Leading Experts

Live 1-1 coding classes to unleash the Creator in your Child

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Register Now & Win Upto 25% Scholorship

Thank you for registering.

Register Now and Win Upto 25% Scholorship for a Full Academic Year !

Enter Your Details

Registration done!

Guest

IIT JEE Courses

One Year IIT Programme

Two Year IIT Programme

Crash Course

NEET Courses

One Year NEET Programme

Two Year NEET Programme

One to One

School Board

Live Online classes

Class 11 & 12

Class 9 & 10

Class 6, 7 & 8

Test Series

JEE test series

NEET test series

C.B.S.E test series

Complete Self Study Packages

FULL COURSE

For class 12th

For class 11th

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7 m +7 n is divisible by 5 is? Answer is given as 1/5 Plz explain

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7m+7n is divisible by 5 is? Answer is given as 1/5 Plz explain

3 Answers

Think You Can Provide A Better Answer ?

Other Related Questions on Magical Mathematics[Interesting Approach]

ASK QUESTION

Answer and earn gift vouchers

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Complete Self Study Package designed by Industry Leading Experts

Live 1-1 coding classes to unleash the Creator in your Child

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Register Now & Win Upto 25% Scholorship

If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7^m+7ⁿ is divisible by 5 is?

Answer is given as 1/5

Plz explain