You have to do a system, lets say x are noble fir trees and y are douglas fir trees,
5x+3y=420
12x+9y=1080
if you solve this you get,
x=60 and
y=40
SO Noble fir trees cost $60 and Douglas fir trees cost $40.
Answer:
in three hours he would have used up 3.75 gallons of gas. He would have 6.25 gallons of gas left in his tank after driving 3 hours.
Step-by-step e
Answer:
Step-by-step explanation:
we know that
The simple interest formula is equal to
where
A is the Final Investment Value
P is the Principal amount of money to be invested
r is the rate of interest
t is Number of Time Periods
step 1
Find the rate of interest
in this problem we have
substitute in the formula above and solve for r
The rate of interest is 
step 2
Find the sum of money that will amount to 25,500 in 5 years, at the same rate of interest
in this part we have
substitute in the formula above and solve for P
Answer:
c)The proof writer mentally assumed the conclusion. He wrote "suppose n is an arbitrary integer", but was really thinking "suppose n is an arbitrary integer, and suppose that for this n, there exists an integer k that satisfies n < k < n+2." Under those assumptions, it follows indeed that k must be n + 1, which justifies the word "therefore": but of course assuming the conclusion destroyed the validity of the proof.
Step-by-step explanation:
when we claim something as a hypothesis we can only conclude with therefore at the end of the proof. so assuming the conclusion nulify the proof from the beginning
