Answer:
b
Step-by-step explanation:
just took test
Mean of data = sum of values ÷ number of data
We have three values; 84, 87, and
Sum of values =
=
We want the value of
to give mean between 85 and 90 inclusive
Hence, the value of
is between 84 and 99 inclusive
If you notice the terms, they're
7, -21, 63, -189 and so forth.
7*-3 = -21 and -21 * -3 is 63 and so forth, meaning the "common ratio" is -3.
now, for a common ratio say "r", which is a fraction, namely less than ±1 and more than 0, or |r| < 1 , you do have a convergent sequence.
however this one notice, |-3| is 3, and that's greater than 1 clearly, therefore is divergent, meaning the summation has no finite value.
Answer: 21
4/7 = 12/x
Multiply each side by x, so the x drops out on right side:
(4/7)x = 12
Distribute x:
4x/7 = 12
Multiply each side by 7, so the 7 drops out on left side:
4x = 84
Divide:
x = 84/4
x = 21