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4 years ago

21x40=840, so 21x 42 = Use mental math

Mathematics

1 answer:

Bad White [126]4 years ago

8 0

Answer:

882

Step-by-step explanation:

mental math right ;)

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Determine the miles traveled in 5 hours at a rate of 189 miles in 3 hours

Salsk061 [2.6K]

Hey there,

Question : Determine the miles traveled in 5 hours at a rate of 189 miles in 3 hours

Answer :
3 hours = 189 miles
1 hour = 189 miles / 3 hours
= 63 miles
5 hours = 63 miles x 5 hours
= 315 miles

Hope this helps :))

~Top♥

8 0

3 years ago

What is the midpoint of the line segment with endpoints (-2, -4) and (4,6)?

prohojiy [21]

Answer:

(1,1)

Step-by-step explanation:

use the midpoint formula to find the midpoint of the line segment

7 0

4 years ago

If F(x)=x^3-2x^2, which expression is equivalent to f(I) -2+i,-2-i,2+i,2-i

Romashka-Z-Leto [24]

Hello from MrBillDoesMath!

Answer:

2 - i

Discussion:

Evaluate F(x) = x^3 - 2 x^2 when x = i.

i^2 = -1 for i^3 = i ( i^2) = i (-1) = -i

So F(i) = (i)^3 - 2 (i)^2

= -i - 2(-1)

= -i + 2

= 2 - i

which is the last answer shown

Thank you,

MrB

6 0

4 years ago

A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard devia

Butoxors [25]

Answer:

Probability that their mean is above 215 is 0.0287.

Step-by-step explanation:

We are given that a bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50.

For this, 40 different applicants are randomly selected.

Let X = ratings for credit

So, X ~ N( $\mu=200,\sigma^{2}=50^{2}$ )

Now, the z score probability distribution for sample mean is given by;

Z = $\frac{X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\mu$ = population mean = 200

$\sigma$ = standard deviation = 50

$\bar X$ = sample mean

n = sample of applicants = 40

So, probability that their mean is above 215 is given by = P( $\bar X$ > 215)

P( $\bar X$ > 215) = P( $\frac{X-\mu}{\frac{\sigma}{\sqrt{n} } }$ > $\frac{215-200}{\frac{50}{\sqrt{40} } }$ ) = P(Z > 1.897) = 1 - P(Z $\leq$ 1.897)

= 1 - 0.97108 = 0.0287

Therefore, probability that their mean is above 215 is 0.0287.

5 0

3 years ago

Clair has250 pennies some pennies are in a box the rest are in her bankthere are more then 100 pennies in each place how many pe

9966 [12]

Answer:

In each place there must be more 100 pennies, but as the total 250 pennies, there are several ways that the money is distributed.

Because there may be 101 pennies in the box and 149 pennies in the bank, but it can also be the opposite; in the box 149 pennies and in the bank 101 pennies.

Therefore, there are many options to answer the question, as long as it is met that there are more than 100 pennies in one place.

8 0

4 years ago