You know a1.
So find a2, a3, and so on until a7.
a(1) = 12
a(2) = 16
a(3) = 20
a(4) = 24
a(5) = 28
a(6) = 32
a(7) = 36
Each is 4 more than the previous.
Can be achieved by dividing.
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8 ÷ 9 = 0.8888
Therefore the answer is B
The Order of magnitude for the population of the world is not five
The value of y=29
the value of x=61
There are many ways you can write a ratio. They're all basically the same thing, though. 5:9, 5 to 9, and 5/9 (which is a fraction) are all just different ways to write ratios.