Elitmus
Exam
Numerical Ability
Algebra
If w,x,y and z are distinct odd positive integers,then the maximum value of the expression (w^2+x^2)*(y^2+z^2) can be divisible by?
a)2 b)3 c)5 d)10
Read Solution (Total 12)
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- ANY ODD NUMBER SQUARE WILL GIVE ODD NUMBER ONLY..
SIMILARLY WEN WE ADD 2 ODD NUMBERS WE WILL GET EVEN NUMBER..
WEN WE MULTIPLY 2 EVEN OWE WILL GET EVEN NUBER..
SO THE RESULT OF THE ABOVE EXPRESSION IS AN EVEN NUMBER ONLY..
HENCE IT IS DIVISIBLE BY 2... - 8 years agoHelpfull: Yes(38) No(4)
- Odd*odd=odd
Odd+odd=even
Even*even=even
Eacha and every even no. Is divisible by 2 it is not necessary that every even no. Is divisible by 3,5 or 10 but every even no get divide by 2
So ans is 2... - 8 years agoHelpfull: Yes(7) No(0)
- answer is 4. any odd number square will give odd number only.
(w^2 + x^2) = odd + odd = even i.e divisible by 2
similarly (y^2 + z^2)= odd + odd = even i.e divisible by 2
now , w^2 + x^2) * (y^2 + z^2) = 2*2 = 4 . so the answer is 4 - 8 years agoHelpfull: Yes(6) No(29)
- to maximize the expression...we have to take maximum odd digit positive digits i.e 3,5,7,9
lets say w=3,x=5,y=7,z=9
now, expression = (9+25)*(49+81)= 34*330
which is going to be a multiple of 10
so option d is the correct option - 8 years agoHelpfull: Yes(4) No(15)
- only mr. SAMEER BHATIA's answer is correct because if we have both options 2 and 4 then correct answer will be 4. as far as 2 is concerned, if a no is divisible by 4 then its it will be definitely divisble by 2 so more approprite ans is 4 (2 is implicit with it)
moreover multiplication of 2 even no. is always divisible by 4.
so 4 is correct ans - 8 years agoHelpfull: Yes(1) No(5)
- answer is 2
addition of square of two odd numbers= even
therefore even*even= even (which is divisible by 2) - 8 years agoHelpfull: Yes(1) No(0)
- answer will be 2.
- 8 years agoHelpfull: Yes(1) No(0)
- Answer will be a)divisible by 2
because-
1.square of odd number will be an odd number and then
2.addition of 2 odd number(square of base odd numbers) will give uh an even number.
3.multiplication of 2 even numbers will give uh an even number so it will be divisible by 2.
- 8 years agoHelpfull: Yes(0) No(3)
- positive integers are 1,3,5,7 and the total is 84 and it is divisible by 3
- 8 years agoHelpfull: Yes(0) No(2)
- we have to take the maximum possible value of the expression
so this can be done by only taking values like 3,5,7,9 .
(9+25)* (49+81)= ending with 0;
so it can be divided by 2 , 5 , 10
so in this question , there should be a correction like what is the maximum value or minimum value from which we can divide it - 8 years agoHelpfull: Yes(0) No(1)
- ans...2
bcz (odd no)^2=odd no.
odd no+odd no=even no..
and even no*even no=even no..
(odd^2+odd^2)*(odd^2+odd^2)
=>(odd+odd)*(odd+odd)
=>even*even
=>even so must be divisible by2 - 7 years agoHelpfull: Yes(0) No(0)
- As they are using the term 'between' ,we can't count '1',thats why ans is 4999
- 7 years agoHelpfull: Yes(0) No(0)
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