What is 100 minus x is less than 41

Ahiker stands at an unknown elevation before he ascends 2 miles up a mountain to an elevation of 9 miles. find the elevation of the hiker before his ascent.

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?

What is the area of the original rectangle? 8 cm² 20 cm² 25 cm² 40 cm²