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
Well they both have integers in it there the same thing except your adding and subtracting. <span>Subtraction is the same thing as adding the opposite of the number. </span>
Answer:
Honestly I don’t know I need help
Step-by-step explanation:
Hello!
To find how much chocolate Adi and Suresh receives, you need to convert the percentage to a decimal, then you multiply that decimal by the total number of chocolates, which is 20.
To convert percentages to decimals, divide the percentage by 100, and remove the percentage.
60% / 100 = 0.60
20% / 100 = 0.20
Then, we multiply 0.60 and 0.20 by 20.
0.60 x 20 = 12
0.40 x 20 = 8
Therefore, Adi gets 12 chocolates and Suresh gets 8 chocolates.
The answer is 48/100. As it is out of 100.
