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3 years ago

I need help with #20

Mathematics

1 answer:

Gnom [1K]3 years ago

8 0

What you did is set πr² equal to A then divide the π by both sides so it will cancel on the right side and keep A over π then square root r to cancel the exponent of 2

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Kevin drove 693 miles in 11 hours. At the same rate, how many miles would he drive in 9 hours

rodikova [14]

Answer:

567 Miles

Step-by-step explanation:

5 0

3 years ago

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In a café, I order a cup of tea and a piece of cake and it costs £1.10. The next time I order 2 cups of tea and one piece of cak

defon

Answer:

£0.50

Step-by-step explanation:

t = one cup of tea

c = one piece of cake

t + c = £1.10

2t + c = £1.70

the cost increases by £0.60 (£1.70 - £1.10) when you order one more cup of tea which means that one cup of tea costs £0.60

substitute £0.60 into t + c = £1.10

£0.60 + c = £1.10

rearrange to get c = £1.10 - £0.60 = £0.50

so one piece of cake costs £0.50

7 0

3 years ago

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If a 60 year old buys a $1000 life insurance policy at a cost of $50 and has a probability of 0.954 of living to age 61 find the

ANTONII [103]

Answer:

The expectation of the policy until the person reaches 61 is of -$4.

Step-by-step explanation:

We have these following probabilities:

0.954 probability of a loss of $50.

1 - 0.954 = 0.046 probability of "earning" 1000 - 50 = $950.

Find the expectation of the policy until the person reaches 61.

Each outcome multiplied by it's probability, so:

$E = -0.954*50 + 0.046*950 = -4$

The expectation of the policy until the person reaches 61 is of -$4.

6 0

3 years ago

4. When Megan solved this system using the elimination method, she added the equations together and got the equation 4y = 16. Th

Ede4ka [16]

Hi there!

So, our two equations are:
2x + 3y = 20 and
-2x + y = 4

We can see that the x's will cancel out because they're the same number, opposite signs. Then we're left with 4y = 24.

Divide 24 by 4, which is 6.

y = 6, then we plug that in to the first equation for y:
2x + 3(6) = 20
2x + 18 = 20
2x = 2
x = 1

So, she made her first mistake when adding the equations, adding 20 and 4, she somehow got 16.

The solution to the system is (1,6).

I hope I helped!

6 0

3 years ago

A scientist measure change in the temperature of chemical solution at the start of the experiment , the solutions is at temperat

zhannawk [14.2K]

Answer:

The temperature of the chemical solution after t hours is $-14.96-2.9t\;^{\circ}C$

Step-by-step explanation:

Given that the initial temperature of the chemical solution, $T_0= -14.96^{\circ}C$ .

The rate of decreasing temperature, $R = 2.9^{\circ}C/ hour$

So, after t hours, the temperature of the chemical solution will decrease by $Rt=2.9t^{\circ}C$ .

So, the temperature of the chemical solution after t hours,

$T=T_0-Rt \\\\\Rightarrow T = -14.96-2.9t\;^{\circ}C$

Hence, the temperature of the chemical solution after t hours is $-14.96-2.9t^{\circ}C$ .

4 0

3 years ago