<span>Standard deviation for mean of n objects = (square root n) x s.d. for one
object.
So you need (2.8/0.5)^2 or around 32.</span>
<span>8a + 4b - 7a -3b
=8a -7a +4b -3b
=a +b</span>
I FOUND YOUR COMPLETE QUESTION IN OTHER SOURCES.
PLEASE SEE ATTACHED IMAGE.
For this case we have the following function:
f (x) = 7,400,000 (1,054) ^ x
Where,
x represents time in years.
Substituting f (x) = 15000000 we have:
15000000 = 7,400,000 (1,054) ^ x
Clearing x we have:
(1,054) ^ x = (15000000) / (7400000)
log1.054 ((1.054) ^ x) = log1.054 ((15000000) / (7400000))
x = log1.054 ((15000000) / (7400000))
x = 13.4 years
Rounding to the nearest year:
x = 14 years
Answer:
the population will reach 15,000,000 in 2014.
Triangle WYZ and triangle TWY are congruent, therefore WZ = TW
WZ = TW
3x - 5 = 2x
3x - 2x = 5
x = 5
The value of x is 5