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2 years ago

Pages in a book are numbered from 1 to 1001. How many of these page numbers include the digit 7?

Mathematics

2 answers:

Pie2 years ago

6 0

Answer:

100

Step-by-step explanation:

one digit number=7 (1 page)

two digit numbers=17,27,37,47,67,77,87,97(9)

three digit numbers=

107,117,127,137,147,157,167,177,187,197 (10)

207,217,.................................,277,287,297 (10)

307,317,..................................,377,387,397 (10)

404,..........................................477,487,497 (10)

507,...................................................................(10)

607,....................................................................(10)

707,717,727,737,747,757,767,777,787,797 (10)

807,..............................................................,897 (10)

907,..............................................................,997 (10)

total number of pages=1+9+9(10)=10+90=100

Brilliant_brown [7]2 years ago

6 0

Answer:

Hello :)

Step-by-step explanation:

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(Set up and solve the system, then answer the associated question)

Dimas [21]

9514 1404 393

Answer:

red division: 6 teams
blue division: 5 teams

Step-by-step explanation:

We can let r and b represent the numbers of teams in the red and blue divisions, respectively. The total number of goals scored in each division will be the average for that division times the number of teams in that division.

r - b = 1 . . . . . . there is 1 more red team than blue

4.5r +4.2b = 48 . . . . . . total goals scored per week

Solving by substitution, we have ...

r = b +1

4.5(b +1) +4.2b = 48 . . . . substitute for r

8.7b +4.5 = 48 . . . . . . . . simplify

8.7b = 43.5 . . . . . . . . . . subtract 4.5

b = 43.5/8.7 = 5 . . . . . divide by 8.7

r = b +1 = 6 . . . . . . . . . find r

There are 6 red teams and 5 blue teams.

_____

<em>Additional comment</em>

The basic idea is that you make an equation for each relation given in the problem statement. For a problem like this, you do need to have an understanding of how the average number of goals would be calculated and how that relates to the total goals.

8 0

2 years ago

Solve the equation by factoring. z2 − 6z − 27 = 0

Kisachek [45]

The answer is x= 9 and -3

You must fine 2 number that multiply to equal -27 and add to equal -6

(x-9) (x+3)
Then equal the parts of the binomial to zero

x - 9 = 0
x + 3 = 0

You must get x by its self.
When you do so, you'll have the answer as -3 and 9

7 0

3 years ago

∠1 and ∠2 are complementary angles. m∠1 is 5y+32 and m∠2 is 7y-14. Find m∠2 & show your work.

Ainat [17]

m<1+m<2=90

$\\ \sf\longmapsto 5y+32+7y-14=90$

$\\ \sf\longmapsto 12y+18=90$

$\\ \sf\longmapsto 12y=72$

$\\ \sf\longmapsto y=6$

m<2=7(6)-14=42-14=28[/tex]

7 0

3 years ago

Read 2 more answers

Kevin is a quarterback on the football team.he completed 36 passes during the season.his second-string replacement,Mark complete

anastassius [24]

36 × $\frac{2}{9}$

Since 9 is a factor of 36 you can reduce the 36 to 4 and the 9 to one

Then just multiply what is left

4 <span>× 2 = 8

So, Mark completed 8 passes.</span>

3 0

3 years ago

Which equation describes the same line asy- 3 =-1(x+ 5)?

aliya0001 [1]

The answer would be A

6 0

3 years ago