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DochEvi [55]
3 years ago
9

A student tries out for the track team and runs a lap in 45 seconds. The coach tells her she will have to cut her time by 50% to

make the team. How fast must she run a lap to make the team?
Mathematics
2 answers:
Fiesta28 [93]3 years ago
8 0
Cutting her time by 50% means reducing her time by half. Half of 45 seconds is 22.5 seconds. Therefore, to make the team, she must run a lap in 22.5 seconds.
Scrat [10]3 years ago
5 0

Answer:

Cutting her time by 50% means reducing her time by half. Half of 45 seconds is 22.5 seconds. Therefore, to make the team, she must run a lap in 22.5 seconds.

Step-by-step explanation:

You might be interested in
. How many square feet of grass are there on a trapezoidal field with a height of 75 ft and bases of 125 ft and 81 ft?
Rudiy27
7725 square feet of grass

((b^1+b^2)/2)h
4 0
3 years ago
22% of adults would pay more for environmentally friendly products he randomly select 10 adults find the probability that the nu
Anettt [7]

Answer: 0.383 and 0.6671

Step-by-step explanation:

Take 22%, that is 0.22 to be probability of success.

That means "1-0.22 = 0.78" is the probability of failure.

When dealing with selection in probability mathematics, the combination equation is used.

Probability of selecting number 'r' as a successful outcome from a given number 'n' is given as

nCr * p^r * q^n-r

Where p is the probability of success= 0.22

q is the probability of failure= 0.78

n is the total number of sample =10

r is the varying outcome of number of success.

For the first question, number of success is asked to be everything more than 2, that is probability of choosing 3,4,5,6,7,8,9,10 people with a successful outcome (adults who will pay more for environmentally friendly product.)

Instead of going through the long process of checking probability of success for choosing 3,4,5,6,7,8,9,10 adults who will pay more, we can simply find the probability of choosing 0,1,2 adults who will pay more and subtract the answer from 1.

By doing this, we first check for probability of choosing 0 adult that will pay More and this is gotten by putting r=0 in our probability Formula. The Formula becomes

=10C0 * 0.22^0 * 0.78^10

=1 *1 * 0.0834= 0.0834

Hence, Probability of Choosing 0 adult that will Pay more is 0.0834

To Check for probability of choosing 1 adult that will pay more becomes

=10C1 * 0.22^1 * 0.78^9

=10 * 0.22 * 0.1069 = 0.2352

Hence, Probability of choosing 1adult that will pay more = 0.2352

To Check for the probability of choosing 2adults that will pay more becomes

=10C2 * 0.22^2 * 0.78^8

=45 * 0.0484 * 0.1370 = 0.2984

Therefore the total sum of choosing 0,1,2 adults that are willing to pay more becomes

= 0.0834+ 0.2352+ 0.2984 = 0.617

So to determine the probability of choosing more than 2 adults, that is, 3,4,5,6,7,8,9,10 adults that are willing to pay more, we subtract 0.617 from 1.

This gives 1-0.617 = 0.383

Hence, probability of choosing more than 2 people that are willing to pay more than 2 = 0.383.

To determine the probability of choosing between two and five people inclusive, we follow the same probability formular but r becomes 2,3,4,5 differently.

For probability of choosing 2 adults, we already calculated it to be 0.2984 earlier.

For probability of choosing 3 adults, it becomes

10C3 * 0.22^3 * 0.78^7

=120* 0.0106 * 0.1757 = 0.2235

For the probability of choosign 4 adults, it becomes

10C4 * 0.22^4 * 0.78^6

= 210 * 0.0023 * 0.2252 = 0.1088

For the probability of choosing 5 adults, it becomes

10C5 * 0.22^5 * 0.78^5

= 252 * 0.0005 * 0.2887 = 0.0364

Hence, the probability of choosing between 2 and 5 adults becomes

0.2984 + 0.2235 + 0.1088 + 0.0364 = 0.6671

5 0
3 years ago
a cook needs 12 pounds of flour he wants to spend the least amount of money if a 2 pound bag costs $1.59 and a 5 pound bag costs
Virty [35]
He should buy two 5 pound bags and one 2 pound bag.
4 0
3 years ago
Read 2 more answers
PLEASE HELP! WILL MARK BRAINLIEST!!
Alecsey [184]

Answer:

The y-intercept is (0,1).  The x values at the horiz. intercepts are:

{ (-3+√5)/2, (-3-√5)/2 }.  Graph is that of a parabola that opens down.

Step-by-step explanation:

It'd be helpful to rewrite f(x) = 3-x2+3x-2 with the powers of x in descending order and using " ^ " to denote exponentiation:

f(x) = -x^2 + 3x -2 + 3, or

f(x) = -x^2 + 3x + 1

y-intercept:  let x = 0.  Then f(0) = 1.  The y-intercept is (0,1)

x-intercepts:  let y = f(x) = 0 = -x^2 + 3x + 1.  Let's use the quadratic formula with a = -1, b = 3 and c = 1 to determine the roots of this polynomial.  The discriminant, b^2-4ac, is 9-4(1)(1), or 5.

Thus, there are two real, unequal roots.  They are:

       -3 plus or minus √5

x =  ---------------------------------

                     2


or { (-3+√5)/2, (-3-√5)/2 }

These are your two horizontal intercepts, where the function is zero.

Because the coefficient -1 of the x^2 term is negative, the parabola representing this function opens down.

8 0
3 years ago
6) Find the difference of (4x - 5) and (6x + 8)
Allushta [10]

Answer:

-2x- 13

Step-by-step explanation:

Hi there!

(4x - 5)-(6x + 8)

Open up the parentheses

4x - 5-6x - 8

Combine like terms

4x -6x- 5 - 8\\-2x- 13

I hope this helps!

6 0
3 years ago
Read 2 more answers
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