Math on khan academy

PLS HELP ME GUYS ASAP FOR 4, 5, 6, and 7 (SHOW WORK!!!) + LOTS OF POINTS!

oksano4ka [1.4K]

4)

12/16=21/b

multiply both sides by b
(12/16)b=21

now multiple both sides by (16/12)
b = 21 (16/12) =28

5)
rate is distance / time or time/distance

train travels 279 km per 1.5 hr =270/1.5
or
1.5 hr per 270 =1.5/27p

answer choice a and c matches that.
looking at choice C...270km/1.5hr=5hr/270km

looking at choice A.. 1.5hr/270km=5hr/k km

the units don't match for choice C so the

right answer is A

6)

1.5/270=5/k

multiply both sides by k
(1.5/270)k=21

now multiple both sides by (270/1.5)
k = (270/1.5)21= 900

7) 75 points per 6 game

75 points / 6 games

75/6=P/20

multiply both sides by 20
(75/6)20=P

P=250

8 0

3 years ago

Please help me on problem 8 and 9 of my teacher created problem

Sunny_sXe [5.5K]

Number 8 is C 251.2 formula multiply 40*3.14=125.6 125.6*2=251.2
and 9 is C get the area of the rectangle 15*5=75 and now of the circle 3.14*2.5^2=78.5 now divide 78.5/2=39.25 then add 39.25+75=114.3.

4 0

4 years ago

Jeremy and Arnold are working on a project for math class in which they are to identify the quadratic equation that represents a

denis23 [38]

Answer:

The parabola generated by the expression :

$y=x^2-2x+3$

is the one that better represents a rain gauge above the ground.

Step-by-step explanation:

The function:

a) $y=x^2+11x+24$

Direction of parabola: branches pointing up

Location of vertex relative to x-axis: below

So, the parabola doesn't depict a rain gauge off the ground

b) $y=-x^2-6x-8$

Direction of parabola: branches pointing down

Location of vertex relative to x-axis: above

So, the parabola doesn't depict a rain gauge off the ground

c) $y=x^2-2x+3$

Direction of parabola: branches pointing up

Location of vertex relative to x-axis: two units above

So, the parabola depicts a rain gauge off the ground

d) $y=x^2+4x+4$

Direction of parabola: branches pointing up

Location of vertex relative to x-axis: right on the x-axis

So, the parabola doesn't depict a rain gauge off the ground (this is sitting on the ground)

e) $y=3x^2+21x+30$

Direction of parabola: branches pointing up

Location of vertex relative to x-axis: below

So, the parabola doesn't depict a rain gauge off the ground

5 0

3 years ago

A theater manager is planning an upcoming concert. Regular tickets will cost $12 and student tickets will cost $8. The theater c

anastassius [24]

Let x be the number of regular tickets
Let y be the number of student tickets

At the most, we can seat 200 people (both regular tickets and student tickets holder). So the inequality is given by: $x+y \leq 200$

One regular ticket cost $12, so $x$ numbers of regular tickets cost $12x$

One student ticket cost $8, so $y$ numbers of student tickets cost $8y$

We want to at least get $1000 from the ticket selling, so the inequality is given by: $12x+8y \geq 1000$

The constraint is given by simplifying both inequalities to the lowest term

First, we have $x+y \leq 200$ ⇒ This is already the lowest term
Second, we have $12x+8y \geq 1000$
Simplifying this by dividing each term by 4, we have $3x+2y \geq 250$

The two constraining inequalities are:
$x+y \leq 200$
$3x+2y \geq 250$

7 0

3 years ago

A travel trailer is bought at the price of $35,000. The value decreases at the rate of .25 every year (t). The exponential expre

Colt1911 [192]

The answer might be D I don’t understand either

3 0

4 years ago