Question

the population of a city was 20,000 in the year in 1997.It increased at the rate of 4% p.a.Find the population at the end of the year 2000

Answer 1

Answer:

• 22497

Step-by-step explanation:

You can solve this by 2 methods:

First method:

• (20,000X4)/100=800
• 1998 population will be 20000+800=20800
• (20800X4)/100=832
• 1999 population will be 20800+832=21632
• (21632X4)/100=865.38 (let's take 865 only)
• 2000 population: 21632+865=22497

Second method:

• We will use effective percentage formula
• A+B+(AB/100)
• Here A, B are different percentages, we will use this for 2 times because 3 years are given
• 4+4+(16/100)
• 8+0.16=8.16 (first time)
• 8.16+4+(8.16X4/100)
• 12.16+(32.64/100)
• 12.16+0.3264=12.4864% (second time)
• 12. 4864% of what? Of original population 20,000
• (12.4864X20000)/100=2497.28 (let's take only 2497)
• 20000+2497= 22497

You can approximate at certain level, but I have not done that.... Please tell me, if you have any doubts... Thanks