Average marks of 15 students in a class is 145, maximum marks being 150. If two lowest scores are removed, the average increases by 5. Also, two lowest scores are consecutive multiples of 9. What is lowest score in the.class?
| A. | 126 |
| B. | 117 |
| C. | 108 |
| D. | None of these |
|
Option: C Explanation :
Total marks of 15 students = 15 x 145 = 2175. Click on Discuss to view users comments. |
revise 39. What is the sum upto 20 terms of the series?
2 8 26 80
- + - + -- + -- + ....?
3 9 27 81
| A. | (19.3²⁰+1) / 3²⁰ |
| B. | (19.3²⁰ + 1)/ 2.3²⁰ |
| C. | (19.3²⁰-1)2.3²⁰ |
| D. | (39.3²⁰+1)+2.3²⁰ |
|
Option: D Explanation : 2 8 26 80 - + - + -- + -- + up to 20 terms 3 9 27 81 =(1-1/3)+(1-1/9)+(1-1/9)+(1-1/27) +(1-1/81)+...up to 20 terms =20-(1/3+1/3²+1/3³+1/3⁴+...+1/3²⁰) =20-1/3((1-(1/3)²⁰) / 1-1/3) =20-(3²⁰-1)/2.3²⁰ =(40.3²⁰-3²⁰+1)/2.3²⁰ =(39.3²⁰+1) / 2.3²⁰ Click on Discuss to view users comments. |
revise 48. Three people A, B and C weigh themselves in a particular order. First A, B, C weigh themselves individually and then AB, BC CA and ABC together respectively. Recorded weight for the
last measured is 180 kgs. Then average of the 7 measures is
| A. | 320 kgs |
| B. | 360/7 kgs |
| C. | 720/7 kgs |
| D. | Cannot be determined |
|
Option: C Explanation : Order of measures is A,B,C,A+B,B+C,C+A,A+B+C. Given: A + B + C = 180 Hence, average of the 7 measures [[(A)+(B)+(C)+(A+B)(B+C)+(C+A)+(A+B+C)]] =--------------------------------------- 7 = 4/7 (A+B+C) = 4/7 x 180 = 220/7 kgs Click on Discuss to view users comments. |
A gardener had a number of shrubs to plant in horizontal rows. At first he tried to plant 5 shrubs in each row, then 6, then 8 and then 12, but had always 1 left. On trying 13, in one row he had none left. What is the smallest number of shrubs that he could have had?
| A. | 481 |
| B. | 477 |
| C. | 468 |
| D. | 121 |
|
Option: A Explanation :
Number is 120K + 1= ((13 * 9 + 3) K + 1) Click on Discuss to view users comments. |
Average age of a team of 15 employees is 36. Youngest of them is 20 years old and eldest is 56 years old. Two of them with average age 28 leave the team. If one of the two comes back on the condition that he will be made the team leader, then which of the following can possibly be average age of the new team so formed?
| A. | 35 |
| B. | 36 |
| C. | 38 |
| D. | 39 |
|
Option: B Explanation :
Total age = 15 x 36 Click on Discuss to view users comments. |
