Molly and Melissa swam laps during practice.

Case Study 2

ICE Princess25 [194]

Answer:

good for them i think

Step-by-step explanation:

this doesnt make any sense

4 0

3 years ago

Find the sum of integers from 33 to 47:

ICE Princess25 [194]

Answer:

Step-by-step explanation:There are formulas to work this out, but you can also suss out an answer by a liberal application of critical thinking.

Okay, you want to add 51 + 52 + 53 + … + 99 + 100, right? (The … represents all the numbers in between, in case you were wondering.)

Well, that’s a total of 50 numbers. And if you know anything about addition, you know that it doesn’t matter what order you add them.

So you could also say 51 + 100 + 52 + 99 + 53 + 98 + … and so on.

Let’s see what happens. 51 + 100 = 151. So far so good.

Then, 52 + 99 also equals 151. And 53 + 98 also equals 151. Since there are 50 numbers, that’s 25 pairs that are going to add up to 151.

151 + 151 + 151 + 151 + … (21 more instances of 151).

So we can simplify our workload a bit. Instead of adding up all the numbers by hand, we can just multiply 151 by 25.

151 x 25 = 3775

From that, we can work out a generic formula that will allow you to add any sequence of numbers…without actually adding.

Let a be the first number in the sequence, and let n be the last number in the sequence. The number of numbers is (n - a) + 1. (You have to add 1, because if you just subtract, it’s like you’re losing the lowest number in the sequence).

So…you get the sum by adding the first and last number in the sequence, and then multiplying that result by half of the total number of numbers.

(a+n)((n−a)+12)

an−a2+a+n2−an+n2

−a2+a+n2+n2

−a(a−1)+n(n+1)2

Let’s check to see if it works!

−51(51–1)+100(100+1)2

−51(50)+100(101)2

−2550+10,1002

75502

3775

Note that if the starting number were 1, the formula would simplify to n(n+1)2

8 0

3 years ago

Read 2 more answers

In a study, researchers wanted to measure the effect of alcohol on the hippocampal region, the portion of the brain responsibl

ziro4ka [17]

Answer:

The hippocampus volumes in the alcoholic adolescents are less than the normal volume of 9.02 cm³

Step-by-step explanation:

Let x= the hippocampus volumes in the alcoholic adolescents

We'll conduct a hypothesis test at the 0.01 significance level with

Null hypothesis: x = 9.02 cm³

Alternate hypothesis: x < 9.02 cm³

A sample of 13 alcoholic adolescents gives the parameters

size=N= 13

mean=M= 8.12 cm³

standard deviation= s= 0.8 cm³

According to the sample, with 99% confidence, t statistic for the value X=9.02 can be found using the formula:

t= $\frac{X-M}{\frac{s}{\sqrt{N} } }$ where

M is the sample mean (8.12)
s is the standard deviation of the sample (0.8)
N is the sample size (13)

If we put these numbers in the formula:

t= $\frac{9.02-8.12}{\frac{0.8}{\sqrt{13} } }$ =4.056

One tailed critical value for the sample with 12 degrees of freedom (sample size-1) in 99% confidence level is 2.681.

Since t value (4.056) is bigger than the critical value, we fail to reject the alternate hypothesis, therefore reject the null hypothesis and accept alternate hypothesis.

5 0

3 years ago

Find the simple interest.

forsale [732]

Answer:

$35.20

Step-by-step explanation:

S.I. = (P×R×T)/100

=(160×5.5×4) /100

= (640×55) / 100×10

= (64×55) / 100

= 3520 / 100

= $ 35.20

brainliest plz

3 0

2 years ago

Andreas wants to estimate how many fish there are in a lake. One day he catches 20 fish,marks them,and returns them to the lake.

tensa zangetsu [6.8K]

Answer:

50

Step-by-step explanation:

The ratio of marked fish to caught fish is 4:10, we need to solve for x in 20:x, since 4 * 5 = 20, 10 * 5 = x so x = 50 fish.

8 0

3 years ago