The cost of 3 notebooks and 2 pencils is $5.10. At the same prices, the cost of 2 notebooks and 3 pencils is $4.65. What is the total cost of a 1 notebook and 1 pencil ?

$1.95

Step-by-step explanation:

notebook = n

pencil = p

3n + 2p = 5.10

2n + 3p = 4.65

multiply top equation by 2 and bottom by 3

6n + 4p = 10.20

6n +9p = 13.95

subtract bottom equation from the top equation

-5p = -3.75

divide by 5, negatives cancel out

p  = 0.75

sub p into either equation, I chose the original top equation

3n + 2(0.75) = 5.10

3n + 1.50 = 5.10

subtract 1.50 from both sides

3n = 3.60

divide both sides by 3

n = 1.20

p = 0.75

n + p = 1.95 (the fourth option)

the answer is; biodiversity resulting from few ancestors

adaptive radiation occurs when a population is subjected to a large natural environment with spatial ecological variations. the parts of the population in the different ecologies begin to adapt to their local environments. due to non-random mating across the large populations, this causes the different populations from the large population to speciate within their local environments. they, therefore, diverge to different species sharing a common ancestor.