A truck enters a stretch of road that drops 4 meters in elevation for every 100 meters along the length of the road.

The official answer explanation is a bit confusing. Can you please explain B)?

A truck enters a stretch of road that drops 4 meters in elevation for every 100 meters along the length of the road. The road is at 1300 meters elevation where the truck entered, and the truck is traveling at 16 meters per second along the road. What is the elevation of the road, in meters, at the point where the truck passes t seconds after entering the road?

A) 1300-0.04t

B) 1300-0.64t

C) 1300-4t

D)1300-16t

I had a question about practice question #3 of the Angles, Triangles, and Polygons chapter.

I had a question about practice question #3 of the Angles, Triangles, and Polygons chapter. I understand the logic behind why A)15 is the answer (Triangle Inequality Theorem), but I think that C)22 could also be a possible answer because the problem never specifies whether RS is one of the two congruent sides or the non-congruent side. If RS were the non-congruent side, and 22 was the perimeter, the remaining sides would each be 6.5, which are not integers. Is my reasoning correct?

In question #10 of the backsolving chapter…

In question #10 of the backsolving chapter : in the xy plane, a line containing the points (a, a^3) and (10,40) passes through the origin. Which of the following could be the value of a?

I found the explanation in the answer key to be too time-consuming if I were to solve the equation with backsolving. Can you explain how to solve this question algebraically instead?