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(D stands for dollars and E stands for euros):
1D = 0.89E (9)
50D = 0.89 ∗ 50E (10)
50D = 44.5E (11)
Therefore, we can say that Ali spent 44.5 euros on his trip to Paris.
Now, for the next part, we have to do the opposite:
converting euros to dollars so we can say:
1D = 0.89E (12)
1E = 1 0.89 E (13)
70E = 1 0.89 ∗ 70E (14)
70E = 78.7E (15)
Thus, the answer can written as 78.7 euros, correct to three significant figures.
2.2 Exponential Growth and Decay Exponential growth
Refers to when a population of a sample grows very fast:
for example every hour it doubles.
Exponential decay refers to when a sample population decreases very rapidly:
for example every hour it halves. In either case, there’s always a specific
multiplying factor that’s used to find the value at the next hour. For exponential
growth the factor would be greater than 1 and for decay, it would be less than
1. In either scenario, it would be positive (greater than 0).
2.1 Population Change
Let’s consider population growth as an example. Assume that there’s a
population of bacteria growing in a laboratory. Every hour, the population
doubles. Initially, the population was 2000. Find the population at the 5th hour.
For question like this you have to form an exponential equation, because even
thought you can do it manually to get 4000, 8000, 16000, 32000 and so on,
but sometimes the time can be very big so you need a formula to simplify
things for you.
The general formula for such a case can be written as: P = Po(f) n (16)
Here P represents the final population size,
Po represents the initial population size,
f is the factor by which it’s growing or decaying and
finally n is the total time after which it’s being observed.