Average

Average : Average

Learning Objectives : Learning Objectives How to answer, when the terms are at = difference. Substitution of a person/item Addition/deletion of a item/person How to give weights to items Some actual CAT questions

Q1:There are 7 consecutive integers. The average of the first 5 is n. What is average of all 7 (CAT 2000)? 1. n 2. n + 1 3. n – 1 4.(n+2)/7 : Q1:There are 7 consecutive integers. The average of the first 5 is n. What is average of all 7 (CAT 2000)? 1. n 2. n + 1 3. n – 1 4.(n+2)/7

Slide 4 : Answer is 2nd option.

Q2 : The avg. temp. for Mon., Tues. & Wed. was 36.5c. The avg. for Tues., Wed. & Thurs. was 38.5c. If the temp. on Mon. be 6/7th of the temperature on Thurs., find the temp. on Thurs (CAT 1992). : Q2 : The avg. temp. for Mon., Tues. & Wed. was 36.5c. The avg. for Tues., Wed. & Thurs. was 38.5c. If the temp. on Mon. be 6/7th of the temperature on Thurs., find the temp. on Thurs (CAT 1992).

Slide 6 : Answer is 42 degrees.

Q3 : The avg. salary of 30 officers, in a firm is Rs. 120 & the avg. salary of laborers is Rs. 40. Find the total no. of employees if the avg. salary of the firm is Rs. 50. : Q3 : The avg. salary of 30 officers, in a firm is Rs. 120 & the avg. salary of laborers is Rs. 40. Find the total no. of employees if the avg. salary of the firm is Rs. 50.

Slide 8 : 210 is the answer . The answer is 240.

Q4 : The average marks of a class of 40 students was calculated to be 62.15. It was later discovered that the marks of a student were taken to be 59, instead of 95. Find the real average of the class. : Q4 : The average marks of a class of 40 students was calculated to be 62.15. It was later discovered that the marks of a student were taken to be 59, instead of 95. Find the real average of the class.

Slide 10 : Answer is 63.05.

Q5: Amol takes average of 10 two-digit numbers, by mistake he interchanges the digits of one no. As a result , the avg. increases by 1.8 of the previous avg. If a & b are the digits of that particular no., then what is the value of (b – a) (CAT 2002)?1.3 2.1 3.2 4. None of these : Q5: Amol takes average of 10 two-digit numbers, by mistake he interchanges the digits of one no. As a result , the avg. increases by 1.8 of the previous avg. If a & b are the digits of that particular no., then what is the value of (b – a) (CAT 2002)?1.3 2.1 3.2 4. None of these

Slide 12 : Answer is 3rd option.

Q6 : A boy appears for 5 papers, each of the same number of max. marks. He scores in each of the papers in the ratio of 6: 7: 8: 9: 10. If his avg. score in all the 5 papers together was 60%, then in how many papers did he get more than 50% marks (CAT 2001)? : Q6 : A boy appears for 5 papers, each of the same number of max. marks. He scores in each of the papers in the ratio of 6: 7: 8: 9: 10. If his avg. score in all the 5 papers together was 60%, then in how many papers did he get more than 50% marks (CAT 2001)?

Slide 14 : Answer is 4 subjects.

Q7 :The sum of 4 consecutive two-digit odd numbers, when divided by 10, becomes a perfect square. Which of the following can possibly be one of these four numbers (CAT2006)? 1. 21 2. 25 3.41 4. 67 5.73 : Q7 :The sum of 4 consecutive two-digit odd numbers, when divided by 10, becomes a perfect square. Which of the following can possibly be one of these four numbers (CAT2006)? 1. 21 2. 25 3.41 4. 67 5.73

Slide 16 : Answer is 3rd option.

Slide 17 : THANK YOU