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? 7 15 18 13 7 15 18 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 In a two-digit number, if it is known that its unit's digit exceeds its ten's digit by 2 and that the product of the given number and the sum of its digits is equal to 144, then the number is: 46 24 26 42 46 24 26 42 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the ten's digit be x. Then, unit's digit = x + 2. Number = 10x + (x + 2) = 11x + 2 Sum of digits = x + (x + 2) = 2x + 2 (11x + 2)(2x + 2) = 144 2x2 + 26x - 140 = 0 (x - 2)(11x + 35) = 0 x = 2Hence, required number = 11x + 2 = 24.
Number System What number should come in the place of (?) in the following number series ? 1, 4, 9, 25, 49, ?, 169, 289, 361 11 321 121 225 11 321 121 225 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The series is (Prime No.)²So it is (11)² = 121
Number System Two-third of a positive number and 25/216 of its reciprocal are equal. The number is: 12/5 25/144 5/12 144/25 12/5 25/144 5/12 144/25 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x. Then,2/3 x = 25/216 * 1/xx2 = 25/216 * 3/2 = 25/144 x = 5/12
Number System If the sum of four consecutive numbers is 370, which the following is the third lowest number among them 90 89 91 92 90 89 91 92 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the four consecutive numbers be x, (x + 1), (x + 2), (x + 3) thenx + (x + 1) + (x + 2) + (x + 3) = 370= 4x + 6 = 370∴ x = 364/4 = 91∴ third lowest number among them = x + 1= 91 + 1 = 92
Number System If (17)3 is subtracted from the square of a number, the answer so obtained is 2143. What is the number ? 84 81 82 83 84 81 82 83 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP x² - (17*17*17) = 2143or x² = 2143 + 4913 = 7056∴ x = 84
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