Day 3 Problem A
Math mini-contest for D.Buzz for July 2021
A random integer between -200 and +200 is multiplied by a rational number between -2 and +2. The ranges are inclusive. What is the range of the result rounded to the nearest whole number?
The problem was originally posted at @savvyplayer/julymathday3a.
Answer
between -400 and 400 inclusive
between -400 and 400, including the limits themselves
-400 ≤ n ≤ 400
400 ≥ n ≥ -400
Any of the answers above shall be considered correct.
Solution
The range in the original problem is -200 ≤ n ≤ 200, where n is the random integer. Multiplying the upper and lower limits of the linear inequality with a negative number will reverse the inequality's upper and lower limits, but since the upper and lower limits are the same number, the sign of the multiplier does not affect the result. If the rational number that is used to multiply the range is -2, then 400 ≥ n ≥ -400. If the rational number used to multiply is 2, then -400 ≤ n ≤ 400.
Winner: none
1 HIVE has been transferred to the prize pool, which will be awarded to the participant with the highest number of correctly-answered problems after all the challenge problems in this Math mini-contest for July 2021 have been concluded.
- @lolxsbudoy's answer of "Between -400 and +400" did not have the "inclusive" or "including the numbers themselves" words, so I could not consider his answer correct. Anyway, thanks to @lolxsbudoy for participating.
Mentions: @jfang003, @holovision, @eturnerx (@eturnerx-dbuzz), @ahmadmanga (@ahmadmangazap), @appukuttan66, @paultactico2, @dkmathstats, and @minus-pi
Special mentions: @dbuzz, @chrisrice, @jancharlest, and @mehmetfix