Number System The average of five consecutive even numbers A, B, C, D and E is 42. What is the product of B and D ? 4589 2476 3289 1760 4589 2476 3289 1760 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP A + B + C + D + E/5 = 42∴ C = 42, ∴ B = 40, ∴ D = 44∴ B x D = 40 x 44 = 1760
Number System 4500 * ? = 3375 1/4 2/5 3/4 3/5 1/4 2/5 3/4 3/5 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4500 * x = 3375= x = 3375/4500 = 3/4
Number System (3² x 4² x 5) ÷ 36 = (?)² - 80 14 12 10 16 14 12 10 16 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP (?)² = 3² x 4² x 5/36 + 80= 20 + 80 = 100∴ ? = √100 = 10
Number System A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is: 81 42 18 24 81 42 18 24 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the ten's and unit's digit be x and 8/x respectively. Then, (10x + 8/x) + 18 = 10 * 8/x + x 9x2 + 18x - 72 = 0 x2 + 2x - 8 = 0 (x + 4)(x - 2) = 0 x = 2 So, ten's digit = 2 and unit's digit = 4. Hence, required number = 24.
Number System What is the sum of all the composite numbers up to 20? 128 132 131 130 128 132 131 130 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4 + 6 + 8 + 9 + 10 + 12 + 14 + 15 + 16 + 18 = 132
Number System What is the sum of all the prime numbers from 20 to 40? 118 117 119 120 118 117 119 120 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 23 + 29 + 31 + 37 = 120
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