Question

If we have $24+37=7$ and $12+18=3$ , then find out $54+21$ equals?

Answer 1

Hint: The key to solving these problems is to find the pattern that links them. We can see that if we had added $24$ and $37$ by normal addition, the value would have been $61$ . Now, $61$ is $7$ more than $54$ . Again, if we had added $12$ and $18$ by normal addition, the value would have been $30$ . Now, $30$ is $3$ more than $27$ . If we observe closely, we can see that a pattern has started to form. The pattern is that the value by which the actual addition value (like $61$ and $30$ ) exceeds or deficits its nearest multiple of $27$ (like $54$ and $27$ ) is the additional value for the problem. If that is the case, then the addition value of $54,21$ by normal addition is $75$ . The nearest multiple of $27$ is $81$ . The absolute value of the difference between $75,81$ gives the answer.

Complete step by step solution:
The equations that we are given are,
$24+37=7....\left( i \right)$
$12+18=3....\left( ii \right)$
We may notice that this is no ordinary addition. If it were so, then the RHS of the first equation would have been $61$ and the RHS of the second equation would have been $30$ . So, we have to think of some other way.
We can see that if we had added $24$ and $37$ by normal addition, the value would have been $61$ . Now, $61$ is $7$ more than $54$ . Again, if we had added $12$ and $18$ by normal addition, the value would have been $30$ . Now, $30$ is $3$ more than $27$ . If we observe closely, we can see that a pattern has started to form. The pattern is that the value by which the actual addition value (like $61$ and $30$ ) exceeds or deficits its nearest multiple of $27$ (like $54$ and $27$ ) is the additional value for the problem.
If that is the case, then the addition value of $54,21$ by normal addition is $75$ . The nearest multiple of $27$ is $81$ . $75$ deficits $81$ by $6$ .
Thus, we can conclude that $54+21=6$ .

Note: The difficulty with these types of problems is that we take time to find the pattern. But we should have patience while solving as many questions as possible. Also, we should not write the answer by simple addition, as that would not be the correct answer.