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3 years ago

Three painters can paint three walls in three minutes. how many painters are needed to paint 27 walls in nine minutes?

1 answer:

4 0

There is 3 variable, in this case, painters, walls and time(minutes). You need to find how many painters needed and provided information on the walls and time(minutes).

Increasing walls will cause more painter needed. It was reversed in time which was increased time will cause less painter needed.

In this case, you need to divide the variable walls with time since it reversed so: 27wall/9 minutes
It equal to : 3 walls/minute

Information provided is:
3 painters= 3 walls/3 minutes
Equal to : 3 paintes= 1 wall/minute

To make it 3 walls/minute, the painter needed will be:
(3 walls/minute) / (1 wall/minute) x 3 painters= 9 painters

Answer: 9 painters

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The school is installing whiteboards in 5 classrooms. Whiteboards, including their

Otrada [13]

Answer:

frdg

Step-by-step explanation:

3 0

2 years ago

9/20

NISA [10]

For this case we must find the solution of the following quadratic equation:

$x ^ 2 + 5x + 7 = 0$

Where:

$a = 1\\b = 5\\c = 7$

Then, the solution is given by:

$x = \frac {-b \pm \sqrt {b ^ 2-4 (a) (c)}} {2a}$

Substituting the values:

$x = \frac {-5 \pm \sqrt {5 ^ 2-4 (1) (7)}} {2 (1)}\\x = \frac {-5 \pm \sqrt {25-28}} {2}\\x = \frac {-5 \pm \sqrt {-3}} {2}$

By definition we have: $i ^ 2 = -1$

$x = \frac {-5 \pm \sqrt {3i ^ 2}} {2}\\x = \frac {-5 \pm i \sqrt {3}} {2}$

Thus, we have two complex roots.

Answer:

The equation has no real roots.

4 0

3 years ago

Algebraic fractions<br> x² + 5x+4 /<br> x²+ 4x + 3

Tresset [83]

Answer:

$\frac{x+4}{x+3}$

Step-by-step explanation:

Given

$\frac{x^2+5x + 4}{x^2+4x+3}$ ← factor numerator and denominator

= $\frac{(x+1)(x+4)}{(x+1)(x+3)}$ ← cancel common factor (x + 1) on numerator/ denominator

= $\frac{x+4}{x+3}$

8 0

3 years ago

Lengths of full-term babies in the US are Normally distributed with a mean length of 20.5 inches and a standard deviation of 0.9

mash [69]

Answer:

66.48% of full-term babies are between 19 and 21 inches long at birth

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.

Mean length of 20.5 inches and a standard deviation of 0.90 inches.

This means that $\mu = 20.5, \sigma = 0.9$