Need help, please explain the answer

Mathematics

1 answer:

stellarik [79]3 years ago

7 0

Answer:

7 - x meters

Step-by-step explanation:

This is a difference of squares. The formula for difference of squares is

a^2-b^2 = (a-b)(a+b)

So plug the numbers we know into this formula.

Area = lw

49 - x^2 = (a-b)(7+x)

49 - x^2 = (7-x)(7+x)

The length is 7 - x meters.

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The maximum number of marks attainable at a mathematics competition is 60. Kate obtains 40 marks, Priya obtains 46 marks, and No

Anna71 [15]

Answer: See explanation

Step-by-step explanation:

Total marks = 60

Kate = 40 marks = 40/60 × 100 = 66.7%

Kate gets a bronze medal.

Priya = 46 marks = 46/60 × 100 = 76.7%

Priya gets a silver medal

Nora = 49 marks = 49/60 × 100 = 81.7%

Nora gets a good medal.

4 0

2 years ago

If the weight (in grams) of cereal in a box of Lucky Charms is N(489,6), what is the probability that the box will contain less

Wittaler [7]

Answer:

0.000064 = 0.0064% probability that the box will contain less than the advertised weight of 466 g.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

N(489,6)

This means that $\mu = 489, \sigma = 6$