d Problem 4: The average weight of a group of boys and girls is 38 kgs. The average weight of the boys is 42 kgs, and that of girls is 33 kgs. If the number of boys is 25. find the number of girls. | Job Exam Rare Mathematics (JEMrare) - Solved MCQs
Advertisements

Problem 4: The average weight of a group of boys and girls is 38 kgs. The average weight of the boys is 42 kgs, and that of girls is 33 kgs. If the number of boys is 25. find the number of girls.

Average Calculation 0

Problem 4: The average weight of a group of boys and girls is 38 kgs. The average weight of the boys is 42 kgs, and that of girls is 33 kgs. If the number of boys is 25. find the number of girls.

a) 10              b) 20             c) 15                 d) 17

Solution:

Let the weight of 25 boys be w1,w2,w3,…………w25. Their average weight is 42kg

\Rightarrow \frac{w1+w2+w3+......+w25}{25}=42

Now suppose total weight of boys  w1+w2+w3+…..+w25 = TwB (written shortly);

\Rightarrow \frac{TwB}{25}=42

\Rightarrow TwB=42\times 25

\Rightarrow TwB=1050



Similarly, supposing there are ‘y’ girls, then  for girls we can write;

\Rightarrow \frac{TwG}{y}=33

\Rightarrow TwG=33y

But we are given that average weight of all girls and boys is 38;

\Rightarrow \frac{Weight Of All Girls+Boys}{Number of All Girls+Boys}=38

\Rightarrow \frac{TwB+TwG}{25+y}=38

\Rightarrow \frac{1050+33y}{25+y}=38

\Rightarrow 1050+33y=38(25+y)

\Rightarrow 1050+33y=950+38y

\Rightarrow 1050-950=38y-33y

\Rightarrow 100=5y

\Rightarrow 20=y

So, there are 20 boys.

Digiprove sealCopyright secured by Digiprove © 2021
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  

You may submit a MCQ or maths problem with solution tips here in the comment box below! If you could not solve anyone, you may submit a MCQ or maths problem without solution as well. We will try our level best to solve it for you!

Your email address will not be published.

You may use these <abbr title="HyperText Markup Language">HTML</abbr> tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

All original content on these pages is fingerprinted and certified by Digiprove
en English
af Afrikaanssq Shqipam አማርኛar العربيةhy Հայերենaz Azərbaycan dilieu Euskarabe Беларуская моваbn বাংলাbs Bosanskibg Българскиca Catalàceb Cebuanony Chichewazh-CN 简体中文zh-TW 繁體中文co Corsuhr Hrvatskics Čeština‎da Dansknl Nederlandsen Englisheo Esperantoet Eestitl Filipinofi Suomifr Françaisfy Fryskgl Galegoka ქართულიde Deutschel Ελληνικάgu ગુજરાતીht Kreyol ayisyenha Harshen Hausahaw Ōlelo Hawaiʻiiw עִבְרִיתhi हिन्दीhmn Hmonghu Magyaris Íslenskaig Igboid Bahasa Indonesiaga Gaeligeit Italianoja 日本語jw Basa Jawakn ಕನ್ನಡkk Қазақ тіліkm ភាសាខ្មែរko 한국어ku كوردی‎ky Кыргызчаlo ພາສາລາວla Latinlv Latviešu valodalt Lietuvių kalbalb Lëtzebuergeschmk Македонски јазикmg Malagasyms Bahasa Melayuml മലയാളംmt Maltesemi Te Reo Māorimr मराठीmn Монголmy ဗမာစာne नेपालीno Norsk bokmålps پښتوfa فارسیpl Polskipt Portuguêspa ਪੰਜਾਬੀro Românăru Русскийsm Samoangd Gàidhligsr Српски језикst Sesothosn Shonasd سنڌيsi සිංහලsk Slovenčinasl Slovenščinaso Afsoomaalies Españolsu Basa Sundasw Kiswahilisv Svenskatg Тоҷикӣta தமிழ்te తెలుగుth ไทยtr Türkçeuk Українськаur اردوuz O‘zbekchavi Tiếng Việtcy Cymraegxh isiXhosayi יידישyo Yorùbázu Zulu