Elitmus
Exam
a natural no has exactly 10 divisors including 1 and itself.how many distinct prime factors can this no have?
Read Solution (Total 4)
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- The number can have two distinct prime numbers.
10 can be written as 1*10 and 5*2
By rule (a+1)(b+1) should give 10
So (4+1)(1+1)=10.
thus two distinct prime numbers. - 11 years agoHelpfull: Yes(10) No(12)
- actually options for these question are:
a)only 1 b)either 1 or 2 c)2 prime factors d) either 1 or 2 or 3 prime factors
write sequence such that you invove minimum number of prime numbers in the sequence:
involve only 1 prime number i.e., 2 and write sequence upto 10 number in the following procedure:
->1 2 4 8(2*4) 16(8*2) 32(16*2) 64(16*4) 128 256 512 1024:
number is 1024 having 10factors including 1 and itself including 1 prime factor i.e., 2
now involve 2 prime numbers 2 and 3 by u r self in the sequence
->1 2 3 6 12 18 24 36 54 72:number is 72 and no of primes is 2(i.e., 2 and 3)
similarly another sequence in the same way
-> 1 2 3 5 10 15 20 30 40 50 :number is 50 and no of prime factors is 3 i.e., 1,2,3
so from all the above conditions the answer is d) either 1 or 2 or 3 - 11 years agoHelpfull: Yes(5) No(11)
- 10=10*1
in this case a no can have one single prime no as a divisor.
eg 512=2^9
this will have exactly(9+1)=10 divisors and only 2 as a prime no divisor.
10=5*2
in this case the number may have 2 prime no as divisors.
so the answer is- 1 or 2 - 11 years agoHelpfull: Yes(5) No(1)
- what is the xaact soln......@ravi,karthiga???
- 11 years agoHelpfull: Yes(0) No(0)
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