The answer is B
- <span>"More" means added to, or addition. So 7 more than 'A number' is: </span><span>d + 7</span>
Answer:
the common ratio is either 2 or -2.
the sum of the first 7 terms is then either 765 or 255
Step-by-step explanation:
a geometric sequence or series of progression (these are the most common names for the same thing) means that every new term of the sequence is created by multiplying the previous term by a constant factor which is called the common ratio.
so,
a1
a2 = a1×f
a3 = a2×f = a1×f²
a4 = a3×f = a1×f³
the problem description here tells us
a3 = 4×a1
and from above we know a3 = a1×f².
so, f² = 4
and therefore the common ratio = f = 2 or -2 (we need to keep that in mind).
again, the problem description tells us
a2 + a4 = 30
a1×f + a1×f³ = 30
for f = 2
a1×2 + a1×2³ = 30
2a1 + 8a1 = 30
10a1 = 30
a1 = 3
for f = -2
a1×-2 + a1×(-2)³ = 30
-10a1 = 30
a1 = -3
the sum of the first n terms of a geometric sequence is
sn = a1×(1 - f^(n+1))/(1-f) for f <>1
so, for f = 2
s7 = 3×(1 - 2⁸)/(1-2) = 3×-255/-1 = 3×255 = 765
for f = -2
s7 = -3×(1 - (-2)⁸)/(1 - -2) = -3×(1-256)/3 = -3×-255/3 =
= -1×-255 = 255
Answer:
Area of the shaded region = 6.88 cm²
Step-by-step explanation:
Area of the shaded region = Area of the rectangle - Area of the semicircle
Area of the rectangle = Length × Width
Length of the rectangle = AD = 8 cm
Width of the rectangle = OP = 4 cm [OP, OB and OC are the radii of the circle which are equal in measures]
Area of the rectangle = 8 × 4 = 32 cm²
Area of the semicircle = 
= 
= 
= 25.12 cm²
Area of the shaded region = 32 - 25.12
= 6.88 cm²
Answer:
E. 0
Step-by-step explanation:
There isn't any guarantee that there are <em>any </em>people that have their birthdays in the same month based on what you're given, so your answer would be 0.
Just by estimating, 54% is a little over 1/2 of 168. You know by that, that neither A or B is close. The real answer is 90.72, so if your instructor wants you to round up, it would be D
