A two digit number is such that its 7 multiple is a perfect square. Sum of all such possible two digit numbers will be

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27 Mar 2015 Two digit numbers A two digit number is such that its 7 multiple is a perfect square. Sum of all such possible two digit numbers will be: OPtion
1) 85
2) 91
3) 95
4) 100
5) 109
6) 112
7) 113
8) 121
9) 125
10)131; Correct Option: 2 Best Solution (26)

Surit Datta 9 years AGO

Two such numbers are possible
this are,
28 and 63
28*7 = 196
63*7 = 441
so summation of 28 and 63 is 91
so option 2
that's it.

Like? Yes (26) | No (4)

Sanu Panji 9 years AGO

7*99= 693. so squre will bw less then 693 and number will be less then |sqrt(693)|=26
also the squre will have 7^2 as a factor. there are two of this kind.
14^2=196
21^2=441

so two number is 196/7=28 and 441/7=63
sum= 28+63 =91

Like? Yes (4) | No

MRITUNJAY 9 years AGO

number will be 28 and 63.
when multiply by 7.
28*7=196=14^2
63*7=441=21^2
sum will be=63+28=91

Like? Yes (2) | No

Yathiraj 9 years AGO

2 digit numbers whose multiple of 7 is a perfect square are 28 & 63.
Hence, 28+63 = 91

Option 2.

PL/SQL program
===============
declare
v_sum number := 0;
v_sqrt_val number;
begin
for i in 10..99
loop
v_sqrt_val := sqrt(i*7);

if v_sqrt_val = trunc(v_sqrt_val) then
v_sum := v_sum + i;
dbms_output.put_line('i: ' || i);
end if;
end loop;

dbms_output.put_line('sum of all such 2 digit numbers ' || v_sum);
end;
/

Like? Yes (2) | No

Meenakshi 9 years AGO

The only possible two digit combinations whose 7 multiple is perfect squares are:63 and 28
The sum of digits are:63+28=>91

Like? Yes (2) | No

Prithwijit Ghosh 9 years AGO

1*1*7=7 its 1 digiys
2*2*7=28
3*3*7=63
4*4*7=113 its 3 digits
So answer will be 28+63=91

Like? Yes (2) | No

prem kishor 9 years AGO

these numbers are 28 and 63.
because 7*_*_
for perfect square one 7 should be and second banks can be 1,4,9.but if we put 1,then7*1 is single digit.
so, 7*4, and 7*9 two digit numbers are possible.

Like? Yes (2) | No

anureet 9 years AGO

when 7{4+9+16+.........) is such sum
when 7{13}=91
7{4+9+16}=203

Like? Yes (2) | No

Pragati Rode 9 years AGO

Find the 2 digit number which is multiple of 7...
14, 21,28 ...98
but there are two numbers i.e. 28 n 63
multiplying by 7 to these numbers we get perfect square.
addition of these two numbers is 91

Like? Yes (2) | No

sravani 9 years AGO

7*4*7 so num is 28
7*9*7 so sum is 63
7*16 is 3digit
so sumof these two is 91

Like? Yes (1) | No

GIRISH TYAGI 9 years AGO

7*4*7=28*7=196 AND 7*9*7=63*7=441

Like? Yes (1) | No

Devendra Marghade 9 years AGO

28 & 63 are such a two numbers which results into squares, when multiplied by 7
28*7=196 and
63*7=441
So Sum 28+63=91
Ans: 2)

Like? Yes (1) | No

Jaspalsingh Parmar 9 years AGO

28 and 63

Like? Yes (1) | No

Jay parmar 9 years AGO

Optn 2

Like? Yes (1) | No

aman aditya 9 years AGO

two nember are 28,63
so
28+63=91

Like? Yes (1) | No

rakesh 9 years AGO

28,63
28+63=91

Like? Yes (1) | No

Srinivas 9 years AGO

7*28=196
7*63=441
so 63+28 = 91

Like? Yes (1) | No

SUSHANT KUMAR 9 years AGO

two digit no whose 7 multiple is a perfect square are 28 and 63
28*7=196 which is a perfect square
63*7=441 which is a perfect square
hence the sum is 28+63=91.

Like? Yes (1) | No

pasupuleti pranavasree 9 years AGO