1800-150-456-789
FlagBACK
Flag IIT JEE Entrance Exam> If r,s,t are prime numbers and p,q are th...
question mark

If r,s,t are prime numbers and p,q are the positive integers such that L.c.m of p,q is r2s4t2., then the total number of ordered pairs(p,q) is ??

Abhinav Acharya , 10 Years ago
Grade 11
anser 2 Answers
Abhishek Singh

Last Activity: 10 Years ago

no. of pais possible=3*5*3=45
 

Abhishek Singh

Last Activity: 10 Years ago

sorry it is incorrect solution, i mistakened it for factors rather than lcm question
Correct solution
Selection for p &q
 p                                      q                     ways
r0                                                 r2                                   1
r1                                                  r2                                  1
r2                                                   r0 ,r1,   r2                      1
 
Total way to select r=5
s0                             s4                                            1 way
s1                             s4                                            1 way 
s2                             s4                                            1 way
s3                              s4                                           1 way
s4                             s0,s1,s3,s4                     5 way
 taota ways to select r=9
similarly for t=5
total ways = 5*9*5= 225

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...

Other Related Questions on iit jee entrance exam

question mark
My rank is 29k, General, should I opt for any state college cse branch or some Nits in which in which I am getting ECE , chemical, mechanics etc....
iit jee entrance exam
0 Answer Available

Last Activity: 2 Years ago

question mark
How is Ranquer Eduzone,comparing, Akash,Fitjee,Resonance,Naryana
iit jee entrance exam
0 Answer Available

Last Activity: 2 Years ago

question mark
Can class 9th students study syllabus classof 11th
iit jee entrance exam
3 Answers Available

Last Activity: 2 Years ago

question mark
Sum of series 2[n/2] ! [n/2]!/ n! [2Co-2C2+3C2....+[-1]^n[n+1]2Cn] where n is an even positive integer. Kindly provide solution of this question and how to generalise this. How do we know that which expansion will give this?
iit jee entrance exam
1 Answer Available

Last Activity: 2 Years ago

question mark
I m foreigner,How much mark i need to get into IIT??
iit jee entrance exam
1 Answer Available

Last Activity: 2 Years ago