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daser333 [38]
3 years ago
9

a brother is 12 years older than his sister. four years ago, the brother was 3 times as old as the sister is now. how old is the

broter now? a 12 b 14 c 16 d 18
Mathematics
2 answers:
Yakvenalex [24]3 years ago
8 0

Answer:

C. 16

Step-by-step explanation:

Let the brother's age be x.

Let the sister's age be y.

x = y + 12

x - 4 = 3y

Put x as y + 12 in the second equation.

y + 12 - 4 = 3y

y + 8 = 3y

8 = 3y - y

8 = 2y

y = 4

Put y as 4 in the first equation.

x = 4 + 12

x = 16

The brother is 16 years old and the sister is 4 years old.

jasenka [17]3 years ago
6 0

Answer:

C. 16

Step-by-step explanation:

Brother - b years now.

Sister - s years now.

A brother is 12 years older than his sister.

b - s = 12

(b - 4) - brother 4 years ago.

Four years ago, the brother was 3 times as old as the sister is now.

b - 4 = 3s

b - s = 12 ----> s = b - 12

b - 4 = 3s

b - 4 = 3(b - 12)

b - 4 = 3b - 36

36 - 4 = 3b - b

32 = 2b

b = 16

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Answer: its b

Step-by-step explanation:

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3 years ago
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gladu [14]

Answer:

|WX|=2\sqrt{10}

Step-by-step explanation:

To find the distance between two points in there dimensional coordinate system, we use the formula;

d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2}

The magnitude for  w(6 ,-3 , 6)  and x(6, 3, 4)

|WX|=\sqrt{(6-6)^2+(3--3)^2+(4-6)^2}

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|WX|=\sqrt{0+36+4}

|WX|=\sqrt{40}

|WX|=2\sqrt{10}

The correct choice is A.

4 0
3 years ago
Flip a coin 10 times and record the observed number of heads and tails. For example, with 10 flips one might get 6 heads and 4 t
FromTheMoon [43]

Answer:

Theoretical probability = 50%

Experimental probability varies.

See below for explanation.

Step-by-step explanation:

This is a problem on theoretical and experimental probability. The results obtained would enable you understand their differences.

The theoretical probability is the result that is expected to happen, but it isn't always what eventually happens.

The theoretical probability of a coin landing on heads is ½ or 50%. This is same for tails.

The experimental probability is the probability obtained from carrying out the experiment. As this is the result of what actually happens, the experimental probability could be lesser  or greater than or equal to 50%.

You are required to carry out the experiment. This is because the result would vary from person to person as well as from one experiment to the other.

First, make a table for the number of trials, outcome (head and tail each) and the frequency. Pen down the result for each of the experiment carried out. You can use a tally to make it easy for compilation.

See attachment for table.

Theoretical probability of 10 trials:

Head= 5, tail = 5

Theoretical probability of 30 trials:

Head= 15, tail = 15

Theoretical probability of 100 trials:

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So do your experiment and record the results. Afterwards compare your result  which is the experimental probability

for head and tail with the theoretical theoretical.

Also compare your result with that of your classmate.

8 0
4 years ago
Checking account A charged a monthly fee of $5 and a per-check fee of $0.25, and checking account B charged a monthly fee of $6
Genrish500 [490]
First we need to know both the formula of A and B.

The formula of A is
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The formula of B is
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he tuition of $3,200 increased by 5% is: 3,200 + 0.05*3,200 = 1.05*3,200 = $3,360

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$3,360 : 12 = $280

The minimum amount Elizabeth should have saved monthly is $280.

6 0
3 years ago
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