Question

The product of two integers is 960. If one of the integers is -40, then what is the other integer. ​

Answer 1

Answer:

$\huge\underline\bold\red{Answer}$

Let the number be a

According to the question

$- 40 \times a = 960$

$a = \frac{960}{ - 40}$

$a = - 24$

hence, the required number = -24

Answer 2

Answer:

First, mathematically. Let the one positive integer is x, so the other is x+1 since they’re consecutive integer. Then we get x(x+1) = 240, so x^2 + x - 240 = 0. By quadratic formula we get x = (-1 + sqrt(1+960))/2 = 15 (i’m not talking about x = -16 since x must be positive). So we get x= 15 and x+1 = 16. 15 and 16 is the answer.

Second, mentally. Since 240 ended with an 0, so one of integer must be ended with an 0 or 5. Since 10^2 = 100 much less than 240 and 20^2 = 400 much more than 240. So we conclude x = 15, and sinc 15^2 = 225 < 240 so we know that the other integer must be 16. 15 and 16 is the answer.