Xi'an, China
34x60n.miles=2,040 nautical miles
109x60n.miles=6,540 nautical miles
2,040+6,540=8,580 nautical miles. (this one is closer)
Los Angeles, USA:
34x60n.miles=2,040 nautical miles
118x60n.miles=7,080 nautical miles
2,040+7,080=9,120 nautical miles. (this one is further)
B. Built on drained and filled lake beds.
Mexico city was built on drained and filled lake beds. The following reasons were the motivations for altering the lake beds and draining it in order to build a city.
1. To reduce the risk of flooding.
2. To protect the city from being invaded.
3. To prevent diseases from spreading.
4. In order to mine the gold under these lake beds
Mohamed and Li Jing were asked to find an explicit formula for the sequence -5\,,-25\,,-125\,,-625,...−5,−25,−125,−625,...Minus,
ANTONII [103]
Answer:
the equation is given as 
Explanation:
As the sequence is given as −5,−25,−125,−625,...
From this the first term is given as
a1=-5
Now the relation between this term and the next term is to be observed.
d=a2-a1=-25-(-5)=-25+5=-20
d=a3-a2=-125-(-25)=-125+25=-100
Now it is observed that the difference is not same this indicates that the relation is not arithmetic.
next up is the geometric sequence so the value of ratio is given as
r=a2/a1=-25/-5=5
r=a3/a2=-125/-25=5
As the ratio is same this indicates, this is a geometric sequence.
Now for the geometric sequence, the value of the general term is given as

Here a1=-5 and r=5 so the equation is given as
