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3 years ago

HELPPPPPPPPPPPP IF U WANNA BE BRAINLEST

Mathematics

2 answers:

dangina [55]3 years ago

7 0

Answer:

between 2.8m and 2.9

Step-by-step explanation:

the real answer is 2.83, so between .8 and .9 is correct

makvit [3.9K]3 years ago

6 0

Answer:

b. between 2.8 and 2.9

Step-by-step explanation:

Simplifying the radical to a decimal, you'll get 2.83, thus the answer for the problem to the nearest tenth is 2.8

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What is the perimeter of a square with a 13ft side

Dafna1 [17]

Perimeter = 2L + 2W
since it’s a square, all sides are equal so
perimeter = 4s
s = 13
so multiply 13 by 4
perimeter = 13*4 = 52

6 0

3 years ago

Read 2 more answers

Evaluate the question below . 12-2

MAXImum [283]

Answer:

=>12-2

=> 10

You're Welcome

Hope this helps you.

<h2>Pls, mark it as the brainliest. I need it.</h2>

8 0

2 years ago

Perimeter of triangle:20

EleoNora [17]

What do you want me to do

4 0

3 years ago

Which equation has no solution? Select all that apply.

melamori03 [73]

Answer:

I think it is C

Step-by-step explanation:

5 0

2 years ago

Initially 100 milligrams of a radioactive substance was present. After 6 hours the mass had decreased by 3%. If the rate of deca

Hitman42 [59]

Answer:

The half-life of the radioactive substance is 135.9 hours.

Step-by-step explanation:

The rate of decay is proportional to the amount of the substance present at time t

This means that the amount of the substance can be modeled by the following differential equation:

$\frac{dQ}{dt} = -rt$

Which has the following solution:

$Q(t) = Q(0)e^{-rt}$

In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.

After 6 hours the mass had decreased by 3%.

This means that $Q(6) = (1-0.03)Q(0) = 0.97Q(0)$ . We use this to find r.

$Q(t) = Q(0)e^{-rt}$

$0.97Q(0) = Q(0)e^{-6r}$

$e^{-6r} = 0.97$

$\ln{e^{-6r}} = \ln{0.97}$

$-6r = \ln{0.97}$

$r = -\frac{\ln{0.97}}{6}$

$r = 0.0051$

$Q(t) = Q(0)e^{-0.0051t}$

Determine the half-life of the radioactive substance.

This is t for which Q(t) = 0.5Q(0). So

$Q(t) = Q(0)e^{-0.0051t}$

$0.5Q(0) = Q(0)e^{-0.0051t}$

$e^{-0.0051t} = 0.5$

$\ln{e^{-0.0051t}} = \ln{0.5}$

$-0.0051t = \ln{0.5}$

$t = -\frac{\ln{0.5}}{0.0051}$

$t = 135.9$

The half-life of the radioactive substance is 135.9 hours.

6 0

2 years ago