(单词翻译:单击)
每日一题
Mathematics
When an object is placed into water, it displaces a volume of water that is equal to the volume of the object. When a certain object is analyzed, it displaces a volume of 10.5 milliliters (ml) of water. If the density of the object is less than or equal to 1.5 grams per milliliter, which inequality represents the possible mass, m, in grams, of the object? (density = mass/volume)
A.m≥7
B.m≤7
C.m≥15.75
D.m≤15.75
答案和解析
答案：D
解析：
Choice D is correct. It is given that the density of the object is less than or equal to 1.5 grams per milliliter, so the inequality below describes the density of the object.
density≤1.5
Because density is equal to mass divided by volume, the inequality above can be rewritten as mass/volume≤1.5
The volume of the water displaced by the object is equal to the volume of the object. Also, m represents the mass of the object. Substituting 10.5 for volume and m for mass results in the following inequality: m/10.5≤1.5
To determine the values of m that satisfy the inequality, multiply both sides of the inequality by 10.5. The resulting inequality is m≤15.75.
Therefore, the mass of the object must be less than or equal to 15.75 grams. The correct answer is: m≤15.75.
