The population of a city increases 15% annually .If the present population is 20,700 , find the population a year ago..
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The population of a city increases 15% annually .If the present population is 20,700 , find the population a year ago..
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Answer:
Step-by-step explanation:
Let last year population be x
increase% =
15
then , the present year population =
x
+
15
of
x
=
1.15
x
20700
=
1.15
x
so,
x
x
=
20700
1.15
=
18000
let initial population was = 100%
this year it increase 15% , so it becomes = 115%
value of this is given, and we have to find initial ,
so,
115% ---------------- 20700
100% --------------- 20700*100/115 = 18000 (ans.)
[ usually we use CI concept in population problems but since they asked only for 1 year , we don't have to use that, because for first year SI and CI remains same ]
[ if you understand my solution mark it as brainlist ]