Question

A cryptography expert is deciphering a computer code. To do this, the expert needs to
minimize the product of a positive rational number and a negative rational number, given
that the positive number is exactly 7 greater than the negative number. What final
product is the expert looking for?
What’s the answer?

Answer 1

9514 1404 393

Answer:

  -49/4

Step-by-step explanation:

The product of a positive number and a negative number will be negative. Its value will be minimized (most negative) when the magnitudes of the two numbers are the same. That is, the numbers that are 7 apart are symmetrically located about 0, so each has a magnitude of 7/2.

The product being sought is (7/2)(-7/2) = -49/4.