Find the number of divisors of 1080 excluding the divisors which are perfect squares.
A. 28
B. 30
C. 29
D. 31

• A) 28
  
  1080 = 2^3 *3^3 *5^1
  
  total no. of divisors = (3+1)*(3+1)*(1+1) = 32
  
  only 4 divisors 1, 2^2=4 , 3^2=9 & 2^2*3^2=36 are perfect squares
  
  so,number of divisors excluding perfect squares divisors = 32-4 = 28
• 10 years agoHelpfull: Yes(31) No(1)
• @Rakesh,@Rishabh
  Hey..will u tell me how u calculated the no of divisors.
• 10 years agoHelpfull: Yes(3) No(1)
• @vaishnavi
  
  If a number can be written as N= a^p * b^q * c^r ......
  where a,b,c are prime factors
  then no.of divisors is ((p+1)*(q+1)*(r+1))
  
• 10 years agoHelpfull: Yes(3) No(1)
• 1080=2*2*2*3*3*5*1=2^3*3^2*5^1
  total number of divisors=(3+1)*(3+1)*(1+1) = 32
  now 32-4=28
• 10 years agoHelpfull: Yes(0) No(2)
• only 4 divisors 1, 2^2=4 , 3^2=9 & 2^2*3^2=36 are perfect squares
  
• 10 years agoHelpfull: Yes(0) No(0)
• 28,,, total no of divisor=32,divisor perfect square is 4 so which are not perfrect square is 28
• 9 years agoHelpfull: Yes(0) No(0)
• 1080=2^3*3^3*5^1
  here total no of divisors=(3+1)(3+1)(1+1)=32
  now perfect sqares are 2^2,3^2,(2.3)^2,excluding these......29 divisors remains
• 9 years agoHelpfull: Yes(0) No(0)
• The answer is 28
• 4 years agoHelpfull: Yes(0) No(0)