The length and width of a rectangle is the whole meter, and its area is 375 square meters. It is known that its width is 10 meters less than its length. How many meters is the sum of its length and width?

The length and width of a rectangle is the whole meter, and its area is 375 square meters. It is known that its width is 10 meters less than its length. How many meters is the sum of its length and width?

If the width is x meters, the length is (x + 10) meters
x（x+10）=375
x²+10x-375=0
（x+25）（x-15）=0
X = - 25 (rounding off); X = 15
Then:
Width = 15m
Length = 15 + 10 = 25m
So:
Length + width = 25 + 15 = 40m

The area of the ground is 200 square meters, which needs 4 bricks long and 5 bricks wide

The area of each brick is 4 * 5 = 20
So 200 / 20 bricks are needed = 10 pieces

What is the formula for calculating how many points there are in an area? For example, how many points there are in this area, one point every 10 cm, 200 meters long and 100 meters wide

The simplest algorithm: (Note: take an integer after division, not rounding) formula: number of points = (length / interval) * (width / interval) if you want to exclude the points on the sideline, you need to judge: 1. Length / interval, width / interval, all get an integer, then subtract 2 (exclude the points on the upper, lower, left and right sides) formula: number of points = (...)