Averages, weighted average, simple arithmetic mean problems : CAT Coaching classes, Study Material

Question 4 the day : July 16, 2003
The question for the day is a sample practice problem in Simple Average - an Arithmetic Topic and the problem provides an understanding of the different concepts related to Averages.

Question
The average weight of a class of 24 students is 36 years. When the weight of the teacher is also included, the average weight increases by 1kg. What is the weight of the teacher?

1. 60 kgs
2. 61 kgs
3. 37 kgs
4. None of these

Correct Answer - 61 kgs. Correct Choice is (2)

Explanatory Answer

The average weight of a class of 24 students = 36 kgs.

Therefore, the total weight of the class = 24 * 36 = 864 kgs

When the weight of the teacher is included, there are 25 individuals.

The average weight increases by 1kg. That is the new average weight = 37 kgs.

Therefore, the total weight of the 24 students plus the teacher = 25 * 37 = 925

Weight of the teacher = Weight of 24 students + teacher - weight of 24 students

= 925 - 864 = 61 kgs.

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Algebra, Arithmetic & Geometric Progressions, Averages and Mean, Clocks and Calendars, Data Sufficiency, English Grammar, Function, Geometry, Coordinate Geometry, Mensuration, Trigonometry, Interest, Inequality, Mixtures & Alligations, Number System and Theory, Percentages, Profit & Loss, Permutation & Combination, Probability, Ratio, Proportion, Set Language and Theory, Speed, Time & Distance, Races, Pipes & Cisterns And Work & Time, Miscellaneous, General Knowledge.