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3 years ago

If the sum of a number and seven is doubled, the result is four less than the number. Find the number.

Mathematics

2 answers:

wel3 years ago

3 0

Answer: the number is - 18

Step-by-step explanation:

Let the number be represented by x.

If the sum of a number and seven is doubled, the result is four less than the number. The expression would be

2(x + 7) = x - 4

We would open the bracket on the left hand side of the equation by multiplying each term inside the bracket by 2. It becomes

2x + 14 = x - 4

Subtracting 14 and x from the left hand side and the right hand side of the equation, it becomes

2x + 14 - 14 - x =x - x - 4 - 14

x = - 18

MrMuchimi3 years ago

3 0

Answer:

-18

Step-by-step explanation:

Let the number be x.

Double the sum of number and seven is equal to four less than the number.

Expressing it in equation form:

$\[2*(x+7)=x-4\]
$

Simplifying the equation,

$\[=> 2x+14=x-4\]
$

Collecting all terms containing x on one side,

$\[=> 2x-x=-14-4\]
$

$\[=> (2-1)x=-18\]
$

$\[=> x=-18\]
$

Hence the required number is -18

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The speed(S) of a car varies partly directly as its mass(M) and partly directly as the quantity (Q) of fuel in it. When the spee

weeeeeb [17]

Answer:

S varies partly directly as M and Q.

S=C.

S=KMQ+C.

For the first one...

speed=80,m=220,Q=30.

80=K20×30+C.

80=600K+C......(I).equation one.

For the second one....

speed=60,m=300,Q=40.

60=K300×40+C.

60=12000K+C.....(ii). equation two.

Minus eqtn(I) from eqtn(ii).

80=600K+C.

- 60=12000K+C.

K=0.01754~0.018.

Substitute K=0.018 into eqtn(I).

80=600K+C

80=600×0.018+C.

80=10.8+C.

C=80-10.8=69.2.

The relation is S=0.018MQ+69.2

when speed is 100 and mass is 250 find the volume.

100=0.018×250×Q+69.2.

100=4.5Q+69.2.

4.5Q=100-69.2

4.5Q=30.8.

Q=30.8/4.5.

Q=6.8~7litres.

6 0

3 years ago

The university needs to transport 421 fans from the stadium parking lot to the football game. If a van holds 10 people, how many

Tasya [4]

421/10= 42.1 vans since you can’t bring a 0.1 van you’ll have to bring a whole extra van so 43 vans

answer: one person will be in the partially full van

7 0

3 years ago

What is the value of x in theequation 2.5 (6x - 4) = 10 + 4 (1.5 +0.5 x)?

Zarrin [17]

Answer:

x = 2

Step-by-step explanation:

Let's solve your equation step-by-step.

2.5(6x−4)=10+4(1.5+0.5x)

Step 1: Simplify both sides of the equation.

2.5(6x−4)=10+4(1.5+0.5x)

(2.5)(6x)+(2.5)(−4)=10+(4)(1.5)+(4)(0.5x)(Distribute)

15x+−10=10+6+2x

15x−10=(2x)+(10+6)(Combine Like Terms)

15x−10=2x+16

Step 2: Subtract 2x from both sides.

15x−10−2x=2x+16−2x

13x−10=16

Step 3: Add 10 to both sides.

13x−10+10=16+10

13x=26

Step 4: Divide both sides by 13.

x=2

5 0

2 years ago

Olga Decorat blankets with ribbon she has 12 yards of ribbon she uses 22 feet of the ribbon to decorate blankets after she decor

andre [41]

Answer:

14 feet

Step-by-step explanation:

There are 3 feet in 1 yard, so 36 feet in 12 yards. The remaining ribbon will be the original amount less the amount used.

36 - 22 = 14 . . . . feet remaining

3 0

3 years ago

8. A box is filled with candies in different colors. We have 40 white candies, 24 green ones, 12

Darya [45]

Answer:

$P(Green\ or\ Red) = 0.30$

Step-by-step explanation:

Given

$White = 40$

$Green = 24$

$Red = 12$

$Yellow = 24$

$Blue = 20$

Required

$P(Green\ or\ Red)$

The total numbe of candy is:

$Total = 40 + 24 + 12 + 24 + 20$

$Total = 120$

This probability is calculated as:

$P(Green\ or\ Red) = P(Green) + P(Red)$

For each, we have:

$P(Green\ or\ Red) = \frac{Green}{Total} + \frac{Red}{Total}$

Take LCM

$P(Green\ or\ Red) = \frac{Green+Red}{Total}$

$P(Green\ or\ Red) = \frac{24+12}{120}$

$P(Green\ or\ Red) = \frac{36}{120}$

$P(Green\ or\ Red) = 0.30$

8 0

3 years ago