# The population of a town increases by 60 percent every year. If after 2 years from present the population is 87040, then what is the present population?

Free Practice With Testbook Mock Tests

## Options:

1. 36000

2. 34000

3. 38000

4. 32000

### Correct Answer: Option 2 (Solution Below)

This question was previously asked in

DSSSB LDC Official Paper 2 (Held on : 18 Aug 2019 Shift 3)

## Solution:

Given:

Rate of increase of population = 60% every year,

Time = 2 years,

Population after 2 years = 87040

Formula Used:

If a quantity increases at the rate of R% in time n, then the final quantity

Final quantity = Initial quantity × {1 + (R/100)}n

where,

R = Rate of increase of quantity

n = number of periods

Calculation:

Let the present population or the initial population and final population of the town be Pi and Pf respectively.

Now,

According to question,

Pf = Pi × {1 + (R/100)}n

⇒ 87040 = Pi × {1 + (60/100)}2

⇒ 87040 = Pi × {(100 + 60)/100}2

⇒ 87040 = Pi × (160/100)2

⇒ 87040 = Pi × (8/5)2

⇒ Pi = 87040 × (5/8) × (5/8)

⇒ Pi = 1360 × 5 × 5

⇒ Pi = 34000

∴ The present population of the town is 34000.
{"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "url": "https://testbook.com/question-answer/the-population-of-a-town-increases-by-60-percent-e--60b8abe49273c84db3ed02ad", "fetch_time": 1627424533000000000, "content_mime_type": "text/html", "warc_filename": "crawl-data/CC-MAIN-2021-31/segments/1627046153491.18/warc/CC-MAIN-20210727202227-20210727232227-00369.warc.gz", "warc_record_offset": 571615230, "warc_record_length": 18995, "token_count": 375, "char_count": 1139, "score": 4.40625, "int_score": 4, "crawl": "CC-MAIN-2021-31", "snapshot_type": "latest", "language": "en", "language_score": 0.8006454110145569, "file_path": "/sailhome/yjruan/project/latent-lm/data/processed/finemath-4plus/finemath-4plus/train-00020-of-00064.parquet"}