1. can't be determined cause no info given on the rate of which the population is growing.
2. can't be determined/not true because the initial population of a could be less than b.
3. can't be determined/not true because we don't have enough info to tell how fast they grow and decline.
A is the answer because the key word is TOTAL and EACH
One way in which to approach this problem would be to treat it as an equation of ratios and to cross multiply:
<span>[(4x + 15) / 5x)] = 1/2 could be written as:
4x + 15 1
----------- = ---
5x 2
Then 8x + 30 = 5x
3x = -30, and so x = -10 (answer). Be certain to check this answer through substitution!
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Answer:

Step-by-step explanation:
Probability of getting a 7 + Probability of not getting a 7 = 1.
Odds against drawing a 7 = Probability of not getting a 7.
We could calculate the probability of getting a 7 and subtract 1 from it to get the answer.
There a four sevens in a deck of card, one of each kind.
Probability of getting a 7 = 

P(not getting a 7)
Answer is d. -5/3 because y2-y1 =x2-x1