Answer:
The answer is A, a total of 12 students spend 31 or more hours online per month.
Step-by-step explanation:
From the hours of 31 to 65 there are twelve students.
Step-by-step answer:
Answer to problems of this kind is the reciprocal of the harmonic mean of the time required.
We need to find the average of the speeds, not the average of the time.
The respective speeds are 1/3 and 1/4.
The average of the speeds is therefore (1/3+1/4)/2 = 7/24 (harmonic mean of the time taken).
The time required is therefore the reciprocal of the unit speed,
T = 1/(7/24) = 24/7 = 3 3/7 minutes, or approximately 3.43 minutes.
Answer:
(B) The inequality that represents this relationship is 
Step-by-step explanation:
Let us assume the given number = x
⇒ 3 times the given number = 3 (x) = 3x
Square of the given number = 
Now, According to the question:
The difference of (3 x) and 15 is no less than 
⇒ 
or, 
Hence, the given inequality is represented as 
Answer:
18000/67 是 268.657
希望有帮助:)
Step-by-step explanation: