Before compairing the price of the different plans, fill in the blanks below for the per minute price, and then add the monthly fee and find the real per minute price.

Plan A - 250 anytime minutes for $30 per month

100min 250min 500min
30$ monthly fee
45 cent additional minutes
Price per minute

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

Solve the equation - 2(m -30) = -6m a-15 b-13 c-8 d8