So Sahra is 3 times as old as her daugter. That means that the sum of their age is the daughters age times 4.
We can prove that by saying the daughters age is x. Sahra's age must be 3x. Their sum must be x+3x = 4x.
So to get the daughters age we divide the sum by 4, which is 8.
D....the empty weight is 160gr
The area of the scale drawing would be 1080 square centimeters or (1080 cm^2). I got this answer through first finding the area of the classroom in feet (which is A= lw = [18][20] = 360 ft^2) and then I proceeded to converting it to centimeters via given scale factor (3 cm = 1 foot) and had the answer of 1080 centimeters squared.
The distance between the points is 16