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3 years ago

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7. The speed of one car is 20% less than the speed of a second car. What per cent more time does the first car need to travel th

e same route as the second car?

1 answer:

9966 [12]3 years ago

7 0

Answer:

25% or more

Step-by-step explanation:

t1 = d1/v1 , t2 = d2/v2.

d1 = d2 , and v1 = 0.8 v2

t1 / t2 = d1/d2 x v2/v1 = v2/v1 ( as d1 = d2 )

t1/t2 = v2 / v1 = v2/0.8 v2 = 1/0.8 = 1.25

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In a doctor's waiting room, there are 14 seats in a row. Eight people are waiting to be seated. There is someone with a very bad

diamong [38]

Answer: 12,972,960

Step-by-step explanation: There are 14 chairs and 8 people to be seated. But among the 8. three will be seated together:

So 5 people and (3) could be considered as 6 entities:

Since the order matters, we have to use permutation:

¹⁴P₆ = (14!)/(14-6)! = 2,162,160, But the family composed of 3 people can permute among them in 3! ways or 6 ways. So the total number of permutation will be ¹⁴P₆ x 3!

2,162,160 x 6 = 12,972,960 ways.

Another way to solve this problem is as follow:

5 + (3) people are considered (for the time being) as 6 entities:

The 1st has a choice among 14 ways

The 2nd has a choice among 13 ways

The 3rd has a choice among 12 ways

The 4th has a choice among 11 ways

The 5th has a choice among 10 ways

The 6th has a choice among 9ways

So far there are 14x13x12x11x10x9 = 2,162,160 ways

But the 3 (that formed one group) could seat among themselves in 3!

or 6 ways:

Total number of permutation = 2,162,160 x 6 = 12,972,960

5 0

3 years ago

5.47 - (-2.8) pls help me

Dominik [7]

Answer:

8.27

Step-by-step explanation:

subtracting a negative number creates a positive

two negatives = a positive

6 0

3 years ago

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Solve for x. x + 3 = 10

ICE Princess25 [194]

Answer:x=7

Step-by-step explanation:

X+3=10

-3 -3

X=7

5 0

3 years ago

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If log_10(x) = 3 + log_10(y), then find x/y

Lina20 [59]

Answer:

1000

Step-by-step explanation:

$log_{10}x = 3 + log_{10}y$
$log_{10}x - log_{10}y = 3$
$log_{10}(x/y) = 3$
$x/y = 10^3$
$x/y = 1000$

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2 years ago

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A football is kicked into the air. The height of the football can be modeled by the equation

Alinara [238K]

Answer:

x = 0 and x = 1

Step-by-step explanation:

Given that,

A football is kicked into the air. The height of the football can be modeled by the equation :

$h = -16x^2 + 16x$

Where

h is the height reached by the ball after x seconds

When it touches the ground, h = 0

So,

$-16x^2 + 16x=0\\\\16x(-x+1)=0\\\\x=0\ and\ x=1$

So, it will touch the ground at x = 0 and x = 1 seconds.

6 0

3 years ago