Question

If $2+3=0;4+5=10;5+6=18;6+7=28;$ then $1+2=??$

• A. $-2$
• B. $-8$
• C. $36$
• D. none of these

Answer 1

The correct option is A $-2$

Method 1:
Square the first number and add one to the second number then subtract second number from the first number.
2 + 3 = 2 ^ 2 - (3 + 1) = 0
4 + 5 = 4 ^ 2 - (5 + 1) = 10
5 + 6 = 5 ^ 2 - (6 + 1) = 18
6 + 7 = 6 ^ 2 - (7 + 1) = 28
1 + 2 = 1 ^ 2 - (2 + 1) = -2
Method 2:
Subtract from first number then multiply with the second number, will give the solution:
2 + 3 = ( 2 - 2 ) *3 = 0
4 + 5 = ( 4 - 2 ) *5 = 10
5 + 6 = ( 5 - 2 ) *6 = 18
6 + 7 = ( 6 - 2 ) *7 = 28
1 + 2 = ( 1 - 2 ) *2 = -2
So, answer is -2.