Elitmus
Exam
Numerical Ability
Number System
If n+x and n+y both are perfect square and x=18, y=90, then how many values of n will satisfied above condition
Read Solution (Total 9)
-
- let n+18= a^2 ........(1)
n+90= b^2 ........(2)
b^2 = n+90
= n+18+72
= a^2+72 (from 1)
b^2-a^2 = 72
(b+a)(b-a)=72.......(3)
factorize 72
1*72 (a,b will be fractions)
2*36 [(19-17)(19+17) then substitute a = 17 and b = 19 then n=271]
3*24 (a,b will be fractions)
4*18 [(11+7)(11-7) then substitute a = 7 and b = 11 then n=31]
6*12 [(9+3)(9-3) then substitute a = 3 and b = 9 then n=-9]
8*9 (a,b will be fractions) - 11 years agoHelpfull: Yes(77) No(2)
- fOR 3 VALUES OF N.
ie. n=31, n=271, n=-9. - 11 years agoHelpfull: Yes(24) No(3)
- for 3 values of n.
i.e. n=31, n=271, n=-9
for n=31
31+18=49=7
31+90=121=11
for n=271
271+18=289=17
271+90=361=19
for n=-9
-9+18=9 =3
-9+90=81 =9 - 11 years agoHelpfull: Yes(11) No(1)
- for n=31 n+x=49 and n+y=121
for n=271 n+x=289 and n+y=361
- 11 years agoHelpfull: Yes(3) No(6)
- only 1 value i.e. n=31
- 11 years agoHelpfull: Yes(2) No(16)
- n=31 and n=-9
- 11 years agoHelpfull: Yes(2) No(7)
- 31+18=49
31+90=121
Are the Perfect squares.
Ans: n=31 - 11 years agoHelpfull: Yes(1) No(7)
- yes only one solution n=31
for n=271 n+y=351.I wrote 2 soltions earlier by mistake.
only one solution is possible - 11 years agoHelpfull: Yes(1) No(9)
- only one ......n =31
31+18=49 (perfect square of 7)
31+90=121 (perfect sqaure of 11) - 11 years agoHelpfull: Yes(1) No(4)
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