If the 10 books are all different, we have:
• 10 ways of selecting the first book,
,
• 9 ways of selecting the second book,
,
• 8 ways of selecting the third book,
,
• 7 ways of selecting the fourth book.
The total number of ways to arrange 4 of the 10 books is:

Answer
There are 5040 ways of arranging the books.
Answer:
B= 70, C= 50
Step-by-step explanation:
120=15x+5+22x+4
120=37x+9
111=37x
X=3
C: 15×3+5=50
B: 22×3 +4= 70
Answer:
not enough info
Step-by-step explanation:
Answer: C . 147π / 4 mi²
Concept:
The sector is the part of a circle is enclosed by two radii of a circle and their intercepted arc.
A = (θ / 360) πr²
θ = angle of the sector
π = constant
r = radius
Solve:
<u>Given variable</u>
θ = 270°
r = 7 mi
<u>Given formula</u>
A = (θ / 360) πr²
<u>Substitute values into the formula</u>
A = (270 / 360) π (7)²
<u>Simplify exponents</u>
A = (270 / 360) π 49
<u>Simplify by multiplication</u>
A = (147 / 4) π
A = 147π / 4
Hope this helps!! :)
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