Number System Which choice provides the answer in the following : If 2 * 3 = 36, 5 * 4 = 400, 6 * 2 = 144, 3 * 3 = 81; then, 5 * 5 = ? 425 625 525 325 425 625 525 325 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 625
Number System When (21)² is subtracted from the square of a number the answer obtained is 1584. What is the number ? 55 65 45 35 55 65 45 35 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be x.According to the question,x² - (21)² = 1584= x² - 441 = 1584 = x² = 1584 + 441 = 2025∴ x = √2025 = 45
Number System In how many ways can 5 boys be chosen from 6 boys and 4 girls so as to include exactly one girl ? 60 54 56 58 60 54 56 58 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP One girl can be chosen in 4C1 = 4 ways and 4 boys can be chosen in 6C4 = 15 ways ∴ Total number of ways = 4 x 15 = 60 ways.
Number System If the difference between the squares of two consecutive numbers is 47, what is the smaller number ? 25 24 23 26 25 24 23 26 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be (x + 1) and x.Therefore, (x + 1)² - x² = 47x² + 2x + 1 - x² = 472x + 1 = 47Therefore, x = 46/2 = 23
Number System What should come in place of (?) in the following series ? 10, 19, 30, 43, 58, ? 76 75 78 77 76 75 78 77 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP The series is: +9, +11, +13, +15, +17
Number System The difference between a two-digit number and the number obtained by interchange the two digits of the number is 27. If the sum of the two digits of the number is 13, what is their product ? 39 40 38 37 39 40 38 37 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be 10x + y.∴ 10x + y - (10y + x) = 27or 9x - 9y = 27∴ x - y = 3 .......(I)x + y = 13 .......(II)From eqn (I) and (II)x = 8 and y = 5.So the number = 85Therefore, product = 8 x 5 = 40
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