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3 years ago

Anna drives 45 km to work each day.

Mathematics

1 answer:

Ivahew [28]3 years ago

3 0

Answer:

<em>Anna drove at an average speed of 49.73 km/h</em>

Step-by-step explanation:

<u>Average Speed</u>

If an object moves at different speeds to cover a certain total distance dt in a total time tt, the average speed is:

$\displaystyle \bar v=\frac{d_t}{t_t}$

Anna drives a total distance of dt=45 km each day. One day she drives a distance of d1=25 km at v1=82 Km/h. The time taken for that distance is:

$\displaystyle t_1=\frac{d_1}{v_1}=\frac{25}{82}=0.3049\ h$

She takes t2=36 minutes to drive the remaining distance. 36 minutes is 36/60=0.6 h, thus the total time is:

$t_t=0.3049\ h+0.6\ h=0.9049\ h$

The average speed is:

$\displaystyle \bar v=\frac{45}{0.9049}=49.73\ km/h$

Anna drove at an average speed of 49.73 km/h

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Find the sales tax amount. purchase price = $121.65; tax rate = 11%

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3 years ago

What is the value of the 8 in 826,140

sergiy2304 [10]

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4 years ago

Read 2 more answers

Let A be a set of numbers.

LUCKY_DIMON [66]

Answer:

a. closed under addition and multiplication

b. not closed under addition but closed under multiplication.

c. not closed under addition and multiplication

d. closed under addition and multiplication

e. not closed under addition but closed under multiplication

Step-by-step explanation:

Let A be a set of all integers divisible by 5.

Let $x,y$ ∈A such that $x=5m\,,\,y=5n$

Find $x+y,xy$

$x+y=5m+5n=5(m+n)$

So, $x+y$ is divisible by 5.

$xy=(5m)(5n)=25mn=5(5mn)$

So,

$xy$ is divisible by 5.

Therefore, A is closed under addition and multiplication.

Let A = { 2n +1 | n ∈ Z}

Let $x,y$ ∈A such that $x=2m+1\,,\,y=2n+1$ where m, n ∈ Z.

Find $x+y,xy$

$x+y=2m+1+2n+1=2m+2n+2=2(m+n+1)$

So,

$x+y$ ∉ A

$xy=(2m+1)(2n+1)=4mn+2m+2n+1=2(2mn+m+n)+1$

So,

$xy$ ∈ A

Therefore, A is not closed under addition but A is closed under multiplication.

$Let A=\{2,5,8,11,14,...\}$

Let $x=2,y=5$ but $x+y=2+5=7$ ∉A

Also,

$xy=2(5)=10$ ∉A

Therefore, A is not closed under addition and multiplication.

Let A = { 17n: n∈Z}

Let $x,y$ ∈ A such that $x=17n,y=17m$

Find x + y and xy

$x+y=17n+17m=17(n+m)$

$xy=(17m)(17n)=289mn=17(17mn)$

So,

$x+y,xy$ ∈ A

Therefore, A is closed under addition and multiplication.

Let A be the set of nonzero real numbers.

Let $x,y$ ∈ A such that $x=-1,y=1$

Find x + y

$x+y=-1+1=0$

So,

$x+y$ ∈ A

Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.

Therefore, A is not closed under addition but A is closed under multiplication.

4 0

3 years ago

HELP ASAP PLS IM TIMED

timama [110]

Answer:

1/24 = 0.0417 (3 sf) = 4.17% (3 sf)

Step-by-step explanation:

Probability is how likely something is to happen
The probability of an event happening = (number of ways it can happen) ÷ (total number of outcomes)

With a number cube there are 6 outcomes: 1, 2, 3, 4, 5 or 6

So the probability of rolling any of these 6 numbers is = 1/6

⇒ probability of rolling a 3 = 1/6

The probability of rolling an even number = the probability of rolling a 2 OR a 4 OR a 6 = 1/6 + 1/6 + 1/6 = 3/6

As rolls are independent from any other rolls, the probability of the second and third roll will not be affected by the first or second roll.

We can calculate the chances of two or more independent events by multiplying the chances.

Therefore, the probability of getting an even number AND an even number AND a 3 = 3/6 x 3/6 x 1/6 = 1/24

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3 years ago

Tyler and Chris collect baseball cards. Tyler has 375 cards in his

likoan [24]

Answer:

Chris will need 23.5 packs (rounded 24 , i would say 24)

Step-by-step explanation:

First you need to takes 375-93= 282

then take 282 and divide by 12 since thats how many cards are in a pack.

that gives you 23.5 then just round

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