Question

1+4=5, 2+5=12,3+6=21,5+8=?

Answer 1

The answer is 45

1+4=5 => 1×(4+1)=52+5=12 => 2×(5+1)=123+6=21 => 3×(6+1)=215+8=x => 5×(8+1)=x

so x=45 :)

the rule followed above is 1st number multiplied by (2nd number + 1)

Answer 2

45

the logic is we have to multiply the first digit from the next digit of the second digit.