A species of dolphins is decreasing at a rate of 3.1% per year. If there are currently 20,000 dolphins, how many will there be in 30 years?

Step-by-step explanation:

The dolphin species decreasing rate per year = 3.1 %

The number of dolphins present currently = 20,000

The number of dolphins available after 30 years = ??

By population depreciation formula,

where Pn is the population after 30 years,

P is the current population

R is the decreasing rate per year

T is the time after n years, in this case 30

=

= 7775.76 = 7776.

option a, c,d are correct.

step-by-step explanation:

from the given figure, it is given that z is equidistant from the sides of the triangle rst, then from triangle tzb and triangle szb, we have

tz=sz(given)

bz=zb(common)

therefore, by rhs rule,δtzb ≅δszb

by cpctc, sz≅tz

also, from δctz and δasz,

tz=sz(given)

∠tcz=∠saz(90°)

by rhs rule, δctz ≅ δasz, therefore by cpctc, ∠ctz≅∠asz

also,from δasz and δzsb,

zs=sz(common)

∠zbs=∠saz=90°

by rhs rule, δasz ≅δzsb, therefore, by cpctc, ∠asz≅∠zsb

hence, option a, c,d are correct.

42.4

step-by-step explanation:

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