Answer:
Time machine one = 3.56
Time machine two = 4.56
Step-by-step explanation:
Let machine 2 do the job in x hours
Let machine 1 do the job in x - 1 hours.
The general formula for this problem is
Time = A*B/(A + B)
Givens
Time = 2 hours
B = x hours alone
A = x - 1 hours alone.
#################
x *( x - 1)
======= = 2
(x + x - 1)
(x^2 - x)/(2x - 1) = 2
x^2 - x = 2(2x - 1)
x^2 - x = 4x - 2
x^2 - 5x + 2 = 0
a = 1
b = - 5
c = 2
This gives 2 roots
x = 4.56
x = 0.43
The second root will not work because when 1 is subtracted from 0.43 the time give will be minus, which won't work.
Time for machine 2 is 4.56
The time for machine 1 is 3.56
Check
(A * B)/(A + B) = 2
A = 4.56
B = 3.56
Time = 4.56*3.56/(4.56 + 3.56)
Time = 16.2336/(8.12)
Time = 1.9992
The rounding error in the check comes from the rounding error in the times.
The answer to your question is I honestly have no idea sorry
Answer: the number of years is 7.3 years
Step-by-step explanation:
We would apply the formula for exponential decay which is expressed as
A = P(1 - r)^ t
Where
A represents the population after t years.
t represents the number of years.
P represents the initial population.
r represents rate of growth.
From the information given,
P = 1250
A = 1000
r = 3% = 3/100 = 0.03,
Therefore
1000 = 1250(1 - 0.03)^t
1000/1250 = (0.97)^t
0.8 = 0.97^t
Taking log of both sides, it becomes
Log 0.8 = tLog 0.97
- 0.0969 = - 0.0132t
t = - 0.0969/- 0.0132t
t = 7.3 years
Answer:
C
Step-by-step explanation:
nvm i figured it out just do 7^2 + 8^2
