Number System In how many different ways can be the letters of the word PENCIL be arranged among themselves ? 720 510 860 640 720 510 860 640 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Total six letters are there and hence the number of arrangements = 6! = 6 x 5 x 4 x 3 x 2 x 1 = 720
Number System The average age of seven boys sitting in a row facing North is 26 years. If the average age of first three boys is 19 years and the average age of last three boys is 32 years, what is the age of the b 31 years 30 years 29 years 28 years 31 years 30 years 29 years 28 years ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Age of the fourth boy = (26 x 7 - 3 x 19 - 3 x 32) years = (182 - 57 - 96) years = 29 years
Number System Three numbers are in ratio of 3: 4 :5. If the sum of first & third numbers is more than second number by 52, which will be largest number? 23 65 78 34 23 65 78 34 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 65
Number System Sum of the digits number is 8 and their product is 12. Find the difference between the digits? None 2 6 4 None 2 6 4 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP x + y = 8xy = 12(x – y)2 = (x + y)2 – 4xy (x – y)2 = 64 – 48 => (x – y) = 4
Number System One half of a two digit number exceeds its one third by 6. What is the sum of the digits of the number? 7 5 9 3 7 5 9 3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP x/2 – x/3 = 6=> x =63 + 6 = 9
Number System The sum of the ages of a son and father is 65 years. After 5 years the age of father will be double of the age of son. What is the age of son ? 19 years 18 years 17 years 20 years 19 years 18 years 17 years 20 years ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the age of the son be x and the age of the father be y.Therefore, x + y = 65 ..........(i)or, 2 x (x + 5) = (y + 5)or, 2x + 10 = y + 5or, 2x - y = 5 ...................(ii)From equations (i) and (ii), x = 20, y = 45
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