1. An advertising company charges $40 per half-page advertisement and $75 per full-page advertisement. Michael has a budget of $800 to purchase 13 advertisements. (a) Define a variable for each unknown.
Write a system of equations to represent the situation and solve the system
(b) How many half-page advertisements does Michael purchase?
Show your work.
(c) How many full-page advertisements does Michael purchase?
Show your work.

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.

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.