Question

If \[m\times n\] = m + (m – 1) + (m – 2) +........+ (m – n), evaluate \[7\times 5\] .
a) 25
b) 20
c) 27
d) 18

Answer 1

Hint: For this question, we are going to follow the same steps or pattern as shown in the question itself.

Complete step-by-step answer:
As demonstrated in the question, to evaluate 7 * 5, we are going to take ‘m’ as 7 and ‘n’ as 5.

As demonstrated in the question, we will follow the same pattern to solve 7 *5.

As mentioned in the hint above, we are taking ‘m’ as 7 and ‘n’ as 5.

Since, \[m\times n\] = m + (m – 1) + (m – 2) + ……… + (m – n)

Therefore, \[7\times 5\] = 7 + (7 – 1) + (7 – 2) + (7 – 3) + (7 – 4) + (7 – 5) = 7 + 6 + 5 + 4 + 3 + 2 = 27

Hence, the answer of this question is (c) 27.

This is how we should solve this question. The questions related to this one are also to be solved by following a particular pattern, which is demonstrated.

Note: For solving such questions, one needs to focus on the pattern demonstrated in the question.
Because, if the pattern is not followed properly, or any mistake is done by the student, then the answer so obtained would be wrong.

We also need to substitute the value of the numbers in the variable provided in the question and then solve the question accordingly.

It will be better if we will solve this question step by step, because then only, our answer will come out to be correct, otherwise, it will be incorrect.