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3 years ago

Serena bought 4 packs of pencils and 12 notebooks

Mathematics

2 answers:

Olin [163]3 years ago

6 0

Answer:

Step-by-step explanation:

that is what it said the correct answer was

Anarel [89]3 years ago

5 0

Answer: pencil (x) = 3.00, notebook (y) = 4.00

Step-by-step explanation:

Let pencils be denoted using 'x', and notebooks 'y'.

4x+12y = 60, 14x+7y=70

Let us use the method of elimination. However, neither variable has the same coefficient, so let us multiply the first equation using 7, and the second using 2.

7(4x+12y = 60) => 28x+84y=420

2(14x+7y=70) => 28x+14y=140

Let us subtract the second equation from the first. This eliminates the first variable x, and gives the equation 70y=280

Dividing either side of the equation by 70, we get y=4.

If we substitute (plug in) y=4 for the first equation we get x=3

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a rhombus as an area of 72 ft and the product of the diagonals is 144. What is the length of each diagonal?

SashulF [63]

A = (1/2)(x)(y)

Let x = diagonal 1

Let y = diagonal 2

The product of xy = 144.

This means that x = 12 and y = 12.

So, 12 • 12 = 144

Each diagonal is 12 feet.

Prove:

72 feet = (1/2)(12)(12) feet

72 feet = (1/2)(144) feet

72 feet = 72 feet

6 0

3 years ago

A spinner numbered 1 through 12 is spun. Find the probability that

anastassius [24]

Answer:

$\dfrac{1}{6}$

Step-by-step explanation:

Let A be the event of getting an odd number.

P(A) be the probability of getting an odd number.

Total odd numbers here are 6 i.e. $\{1,3,5,7,9,11\}$

Here, total numbers in the game are 12 i.e $\{1,2,3,....,12\}$ .

Formula for probability of an event E can be observed as:

$P(E) = \dfrac{\text{Number of favorable cases}}{\text {Total number of cases}}$

$P(A) = \dfrac{6}{12}\\\Rightarrow \dfrac{1}{2}$

Let B be the event of getting 11.

P(B) be the probability of getting 11.

Total number of possible cases is 1.

$P(B) = \dfrac{1}{12}$

$P(A \cap B)$ is the probability that we get 11 and an odd number.

Possible number of cases = 1

$P(A\cap B) = \dfrac{1}{12}$

P(B/A) is the probability that we get an 11 given that it is an odd number.

$P(B/A) = \dfrac{P(A \cap B)}{P(A)}\\\Rightarrow \dfrac{\dfrac{1}{12}}{\dfrac{1}{2}}\\\Rightarrow \dfrac{1}{6}$

Hence, P(B/A) = $\dfrac{1}{6}$

4 0

3 years ago

Read 2 more answers

PLEASEEE HURRY !!!

Morgarella [4.7K]

Answer:

b : $0.22 on edg.

Step-by-step explanation:

7 0

3 years ago

A 250 m train travels through a 2km tunnel at 27 km/hr. How long is it from the time the front of the train enters the tunnel, t

olga55 [171]

Answer:

5 min

Step-by-step explanation:

time taken=distance required to travel/speed of train

total distance train have to cover to just left the tunnel is (lenght of tunnel+length of train) =2km+250m

=2250m

speed of train is 27km/hr

multiply 5/18 to convert in m/s

i.e, (5/18)×27=7.5m/s

now time taken =2250m/(7.5m/s)

=300s

and,300s =5min

4 0

3 years ago

The distance a train travels d is proportional to a constant rate of speed r at different times t which equation shows the relat

Anarel [89]

Answer:

Step-by-step explanation:

d = rt so to isolate r you divide both sides by t, leaving you with r=d/t

its basically speed=distance/time, or s=d/t if that's more farmiliar to you

6 0

3 years ago