1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Fudgin [204]
3 years ago
9

1. The sum of a two-digits number is 13. The tens digit is 8 less than twice the units digit. What is the number?

Mathematics
1 answer:
alexgriva [62]3 years ago
3 0

Answer:

<u>The number is 67</u>

Step-by-step explanation:

<u>Equations</u>

Let's consider the number 83. The tens digit is 8 and the unit digit is 3. Note the tens digit's addition to the number is 80, and the unit's addition is 3. This means the tens digit adds 10 times its value, that is, 83 = 8*10 + 3.

Now, let's consider the number ab, where a is the tens digit, and b is the unit digit. It follows that

Number=10*a+b

The question gives us two conditions:

1) The sum of a two-digits number is 13.

2) The tens digit is 8 less than twice the units digit.

The first condition can be expressed as:

a + b = 13                     [1]

And the second condition can be written as:

a = 2b-8                      [2]

Replacing [2] into [1], we have:

2b-8 + b = 13

Operating:

3b = 13 + 8

3b = 21

Solving for b:

b = 21 / 3 = 7

Substituting into [2]:

a = 2*(7) - 8 = 6

Thus, the number is 67

You might be interested in
normally distributed with mean 24.6 seconds and standard deviation 0.64 seconds;the lower finishing time, the better. If the qua
marshall27 [118]

Answer:

z=1.04

And if we solve for a we got

a=24.6 +1.04*0.64=25.27

So the value of height that separates the bottom 85% of data from the top 15% is 25.27.  

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  

Solution to the problem

Let X the random variable that represent the finishing time of a population, and for this case we know the distribution for X is given by:

X \sim N(24.6,0.64)  

Where \mu=24.6 and \sigma=0.64

Solution to the problem

For this part we want to find a value a, such that we satisfy this condition:

P(X>a)=0.15   (a)

P(X   (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.  

As we can see on the figure attached the z value that satisfy the condition with 0.85 of the area on the left and 0.15 of the area on the right it's z=1.04. On this case P(Z<1.04)=0.85 and P(z>1.04)=0.15

If we use condition (b) from previous we have this:

P(X  

P(z

But we know which value of z satisfy the previous equation so then we can do this:

z=1.04

And if we solve for a we got

a=24.6 +1.04*0.64=25.27

So the value of height that separates the bottom 85% of data from the top 15% is 25.27.  

3 0
2 years ago
Fill in the blanks below in order to justify whether or not the mapping shown
MrRa [10]

Answer:

wheres the picture?

Step-by-step explanation:

6 0
2 years ago
How many acute angles are in a right triangle
garik1379 [7]

Answer:

there are 2 a cute angles in a triangle

5 0
3 years ago
Find the equation of the line (in slope-intercept form) through the points (1,-4) and with slope 5/2.
Phoenix [80]

Answer:

Equation of a line is y = mx + c

Where m is the slope

c is the y intercept

Equation of the line using point

( 1 , - 4) and slope 5/2 is

y + 4 =  \frac{5}{2} (x - 1) \\  \\ y + 4 =  \frac{5}{2} x -  \frac{5}{2}  \\  \\ y =  \frac{5}{2} x -  \frac{5}{2}  - 4 \\  \\  \\ y =  \frac{5}{2} x -  \frac{13}{2}

Hope this helps you

8 0
3 years ago
2l+2w 10 feet by 3.5 feet
Nana76 [90]

Answer:

Step-by-step explanation:

Perimeter of rectangle =2l+2w

10 feet by 3.5 feet

l = 10feet and w = 3.5feet

Perimeter = 2(10) + 2(3.5)

Perimeter = 20 + 7

Perimeter = 27feet

5 0
2 years ago
Other questions:
  • Antonia buys a 5-pound bag of onions at the store for $2.65. To the nearest cent, how much did she pay for 1 pound of onions?
    11·2 answers
  • PLS HELP ASAP GUYS! 50 POINTS!! Match the verbal expression to its correct algebraic expression.
    10·1 answer
  • What tool can you use to measure a ropes length plz answer I need it now plz!!
    11·1 answer
  • Which set of ordered pairs represents y as a function of x?
    12·1 answer
  • HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
    12·1 answer
  • PLEASE ANSWER ASAP<br> expand and simplify the following:<br> a) (√6+√3)(√6-√3) b)(√5-√2)(√2+√5)
    6·2 answers
  • Find the area of a circle with radius of 6<br> inches. (Use 3.14 for 1.)
    11·1 answer
  • Write an equation for a line that goes through (3, -7) and is parallel to the line<br> y = 2x – 17
    6·1 answer
  • Which of the following are perfect squares select all that apply
    9·2 answers
  • Help xdddddddddddddddddddddddddddd
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!