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3 years ago

Evaluate the expression when a = - 4.2 and b = - 3.9 . - 7b + 2a

Mathematics

1 answer:

Delicious77 [7]3 years ago

4 0

Answer:

-35.7

Step-by-step explanation:

1. Plug in a and b to the equation:

7(-3.9)+2(-4.2)

2. Evaluate: -35.7

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The ratio between the number of red and green marbles in a box is 3:7. How many marbles are in the box if there are 20 fewer red

jeyben [28]

Answer:

50 marbles

Step-by-step explanation: The difference between the ratio of the red and green marbles is 4 units and the number value is 20 so its safe to say that 4 units is equal to 20 and thus one unit is 5 and because of the fact that there is a total of 10 units of marbles in the box according to the ratio, just multiply 5 and 10 which you get 50.

4 units = 20

1 unit = 20÷4 = 5

Total = 10 units

10 unit = 5 ×10 = 50

Ans : 50 marbles

3 0

3 years ago

The highest possible z-score that is still in the bottom 95% of the systolic blood pressure distribution is z =−1.645 . Use this

lawyer [7]

Answer:

(1) The value of X is, 151.13.

This score X, is the 95th percentile of systolic blood pressure scores among women. The percentile rank of this score is 95.

(2) The percentage of women have systolic blood pressure in the range 140 to 159 is 9.01%.

(3) The percentage of women having systolic blood pressure below 90 is 21.19%.

Step-by-step explanation:

The random variable X is defined as the systolic blood pressure of women.

The distribution of X is, N (110, 25²).

(1)

The value of z-score that is in the bottom 95% is, 1.645.

Compute the value of X as follows:

$z=\frac{X-\mu}{\sigma}\\1.645=\frac{X-110}{25}\\X=110+(1.645\times 25)\\X=151.125\\\approx151.13$

The value of X is, 151.13.

This score X, is the 95th percentile of systolic blood pressure scores among women. The percentile rank of this score is 95.

(2)

Compute the probability of X between 140 and 159 as follows:

$P(140$

The percentage of systolic blood pressure between 140 and 159 is,

0.0901 × 100 = 9.01%

Thus, the percentage of women have systolic blood pressure in the range 140 to 159 is 9.01%.

(3)

Compute the probability of X below 90 as follows:

$P(X$

The percentage of women having systolic blood pressure below 90 is,

0.2119 × 100 = 21.19%.

Thus, the percentage of women having systolic blood pressure below 90 is 21.19%.

6 0

4 years ago

How much is 11+5+3x2+8x1?

adoni [48]

11+5=16 3x2= 6 8x1= 8 so add it together, 16 + 6 + 8 = 30.

8 0

3 years ago

Read 2 more answers

What is the solution to the following system of linear equations?

Arturiano [62]

Answer:

i think it's B, no solutions

Step-by-step explanation:

because they are parallel to each other

3 0

3 years ago

Read 2 more answers

A certain ferry moves up and down a river between Town A and B. It takes the ferry two hours to travel to Town A and only an hou

Y_Kistochka [10]

Answer:

The distance between two cities is 60 miles.

Step-by-step explanation:

Time taken to travel from B to A = 2 hours

Time taken to travel from A to B = 1.5 hours

Current speed = 5 mph

Let the speed of ferry in still water = u mph

When the ferry moves with the current, it will taken lesser time (i.e. A to B) and when it moves against the current it will take more time (i.e. B to A).

Let the distance between the two cities A and B = D miles

While moving with the current, speed = $(u+5)\ mph$