Number System The average of 7 numbers is 15, that of the first three is 6 and that of the last three is 23. What is the fourth number? 15 18 7 13 15 18 7 13 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4th No. = (Total of 7 Nos) - (Total of first three + total of last 3) = (15 x 7) - (6 x 3 + 23 x 3) = 105 - (18 + 69) =105 - 87 = 18
Number System What is the least number, which is perfect square but contains 2700 as its factor? 10800 1800 2700 5400 10800 1800 2700 5400 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 900 * 3 * 3 = 8100
Number System Sum of the digits number is 8 and their product is 12. Find the difference between the digits? 6 None 4 2 6 None 4 2 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 What is the sum of all the prime numbers from 20 to 40? 117 120 119 118 117 120 119 118 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 23 + 29 + 31 + 37 = 120
Number System What should come in place of question mark (?)? 8 : 1 1 : : 72: 99 109 79 89 99 109 79 89 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let ? = xTherefore 8 : 11 : 72 : xTherefore x = (11 x 72) / 8 = 99
Number System 1260 x 1.45 - 888 x 1.75 = ? 295 273 367 256 295 273 367 256 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? = 1260 x 1.45 - 888 x 1.75= 1827 - 1554 = 273
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