Answer:
18
Step-by-step explanation:
30*0.4=12
This means 40% of 30 is 12 and Ana has completed 12 problems.
30-12 = 18, so she still needs to do 18 problems.
Since an arithmetic sequence is a sequence of numbers and the difference of any two successive members of the sequence is a constant
So this question is arithmetic because it keep minus by 7
from 19 - 7 = 12
12 - 7 = 5
5 - 7 = -2
so common difference is -7
or you can check with arithmetic formular as
=
+ (n−1)d
I will just put in the 4th term which is -2 and n will equal to 4
and
is the 1st term which is 19
-2 = 19 + (4−1)d
-2 - 19 = 3d
d = 
d = -7
Answer: D ; The value of the digit in the ten thousand place is 1/10 the value of the digit in the hundreds place.
If the number before the place you are rounding to is a 5 or more you round up but if it is a 4 or below it stays the same so the answer is 28,000,000