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4 years ago

Please help with these

Mathematics

1 answer:

MatroZZZ [7]4 years ago

8 0

Set up a proportion.

$\frac{3~minutes}{2~questions}$ = $\frac{x~minutes}{12~questions}$

Cross multiply.

2x=36
x=12

It would take her 12 minutes.

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Formula for surface area of a cube: 6a² where a=20.

6 x (20)²
6 x 400
= 2400

Surface area: 2400 cm

----------------------------------------------

Mean absolute deviation: The average distance from each number in the set to the mean of the set.

Mean of the set: $\frac{(3+8+10+12+15)}{5} = \frac{48}{5} = 9.6$

9.6-3=6.6
9.6-8=1.6
10-9.6=0.4
12-9.6=11.4
15-9.6=5.4

Mean of 6.6, 1.6, 0.4, 11.4, and 5.4: $\frac{(6.6+1.6+0.4+11.4+5.4)}{5} = \frac{25.4}{5} = 5.08$

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TELEVISIONS in 1999, 68% of households with tv's subscribed to cable tv. if 8,000 more subscribers are added to the number of ho

Art [367]

Let x be the number of households with TV.

So .68x would be the number of households with cable.

If 8000 were added to the above number, it would be equal to 67,600,000.

Thus we have our equation:

.68x + 8000 = 67600000

Solving for x:

.68x = 67592000

x = 99,400,000

6 0

3 years ago

Broccoil cost 3.14$ a pound at the market if mary bought 2.5 pounds what was the cost

Mars2501 [29]

7.85 dollars because 3.14 is the price of one pound your buying 2.5 so you times 3.14 by 2.5

7 0

3 years ago

If a person invests $100 at 4% annual interest, find the approximate value of

tekilochka [14]

Answer:

$140

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Simple Interest Rate Formula: $\displaystyle A = P(1 + rt)$

P is principle amount
r is rate
t is time

Step-by-step explanation:

Step 1: Define

Identify variables

P = 100

r = 4% = 0.04

t = 10

Step 2: Find Interest

Substitute in variables [Simple Interest Rate Formula]: A = 100(1 + 0.04 · 10)
(Parenthesis) Multiply: A = 100(1 + 0.4)
(Parenthesis) Add: A = 100(1.4)
Multiply: A = 140

5 0

3 years ago

PLEASE HELP ME SOLVE

kirill115 [55]

The time taken for 21000 spectators to vacate the stadium , if only 15 exits are functional is 28 minutes .

In the question ,

it is given that

the time taken to vacate the stadium = 20 minutes

number of exits = 25 exits

capacity of the stadium = 25000 spectators .

given that ,

time taken to exit the stadium varies directly with number of spectators and inversely with the number of exits .

time taken ∝ number of spectators ∝ 1/number of exits .

to remove the proportionality sign , we write the constant

time taken = k * (number of spectators)/(number of exits) .

20 = k * 25000/25

20 = k * 1000

k = 20/1000

k = 2/100

k = 1/50 = 0.02

So, to find the time taken for 21,000 spectators to vacate the stadium, if only 15 exits are functional , we use the formula

time taken = (0.02)*(21000/15)

= 0.02*1400

= 28

Therefore , The time taken for 21000 spectators to vacate the stadium , if only 15 exits are functional is 28 minutes .

Learn more about Equation here

brainly.com/question/23633125

#SPJ1

5 0

2 years ago

Halle's mom sent her to the store to buy some peaches and plums . The total cost of the peaches was $1.88 .The plans cost zero d

VMariaS [17]

Answer:

Halle bought 6 plums from the store.

Step-by-step explanation:

Given:

total cost of the peaches = $1.88

Cost of 1 Plum = $0.33

Total Money paid = $3.86

We need to find the number of Plums.

Let the number of plums be x.

Now we know that Total money paid is equal to Cost of peaches plus Cost of each Plum multiplied with number of plums.

Hence the expression can be framed as;

$1.88+0.33x=3.86$

Now Solving the above expression to find the value of x;

$1.88+0.33x=3.86\\0.33x = 3.86-1.88\\0.33x=1.98\\\\x = \frac{1.98}{0.33} = 6$

Hence Halle bought 6 plums from the store.

4 0

3 years ago