# If 1+2=7; 3+4=31;5+6=71; 7+8=127 then 9+10=?

3,998 views
posted Jul 9, 2015

## 7 Solutions

199
(a*b*2)+(a+b)=c
9*10*2=180
180+9+10=199

solution Jul 10, 2015 by anonymous
1+2=7, 1+2=3, 7-3=4, 4=4x1 (1) / 3+4=31, 3+4=7, 31-7=24, 24=4x6 (6) / 5+6=71, 5+6=11, 71-11=60, 60=4x15, (15) / 7+8=127, 7+8=15, 127-15=112, 112=4x28 (28) , so, 6-1=5, 15-6=9, 28-15=13, (so 9-5=4, 13-9=4,) so, 9+10=19, then if answer is x, so x-19=180 i.e(45x4), so, x=199

(a+b)*b+a

a=9 ,b=10

199

solution Sep 26, 2015 by
then how you will get:
5+6=71

using the same rule.
??
Its working on that also
a=5 b=6 then
(5+6)*6+5 = 11*6+5 = 66+5 = 71
+1 vote

2*n^2 +4*n +1 = 162+ 36+ 1 = 199, where n= 9

solution Aug 13, 2015

(1+2)*2 + 1 = 7
(3+4)*4 + 3 = 31
(5+6)*6 + 5 = 71
(7+8)*8 + 7 = 127
(9+10)*10 + 9 = 199

Ans :- 199

solution Mar 14, 2016

1+2= 1+(1+2)*2 = 7
3+4= 3+(3+4)*4 = 31
5+6= 5+(5+6)*6 = 71
7+8= 7+(7+8)*8 = 127
9+10= 9+(9+10)*10 = 199

solution Mar 15, 2016

y*y+x*x+y+(y-2)
2*2+1*1+2+(2-2)=7
4*4+3*3+4+(4-2)=31
6*6+5*5+6+(6-2)=71
8*8+7*7+8+(8-2)=127
10*10+9*9+10+(10-2)=199

solution Mar 19, 2016 by

a*a+b*b + (a+b-1)=9*9+10*10+(1+10-1)=181+18=199

solution May 7, 2016 by anonymous

Similar Puzzles
–1 vote

If
5 + 4 => 9
3 + 5 => 9
9 + 1 => 9
1 + 6 => 8
4 + 2 => 8
1 + 7 => 7
5 + 6 => 6
3 + 7 => 3
7 + 0 => 0
Then
8 – 1 => ??