Answer:
The rate of decrease is 8%
Step-by-step explanation:
we know that
The general equation for the radioactive decay can be written as:
where
a is the amount in kilograms after time t.
a_0 is the original amount of the substance or y-intercept of the function
r is the decay rate, written in decimals.
t is the time
In this problem we have
so
solve for r
Convert to percentage
Answer:
5
Step-by-step explanation:
n + m -2(m-m)
Combine like terms
n+m+2(0)
n+m
Let m=3 and n=2
2+3
5
Answer:
2.5 km
Step-by-step explanation:
15 minutes is
15 minutes * 1 hour/ 60 minutes = 1/4 hour
15 minutes = 1/4 of an hour
10 km/ hour * 1/4 hour = 10/4 km = 2.5 km
Answer:
314 m²
Step-by-step explanation:
the formula for the surface area of a sphere (As) is
As = 4×pi×r²
the radius r (half of the diameter) is clearly indicated as 5m.
so, As = 4×3.14×5² = 4×3.14×25
I don't even need a calculator for this, as 4×25 = 100
so, As = 100×3.14 = 314
(you know, when multiplying by 10, the decimal point moves right one position. multiply by 100 it moves 2 positions, and so on).
