Number System If the sum of the two numbers is 22 and the sum of their squares is 404, then the product of the numbers is: 44 88 80 40 44 88 80 40 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be x and y. Then, (x + y) = 22 and x2 + y2 = 404 Now, 2xy = (x + y)2 - (x2 + y2) 2xy= 222 - 404 = 484 - 404 = 80xy = 40
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? 13 7 18 15 13 7 18 15 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 The difference between 72% of a number and 49% of the same number is 575. What is 9% of that number ? 275 245 225 295 275 245 225 295 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the no. be x.Therefore, 72% of x - 49% of x = 575Therefore, (72 - 49)% of x = 575Therefore, 9% of x = 575/23 x 9 = 225
Number System What is the least number that should be added to 5200 to make it a perfect square ? 129 275 225 288 129 275 225 288 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP We sec (73)² = 5329 and (72)² = 5184ie 5329 > 5200 > 5184So 129 should be added to make is perfect square.
Number System If the sum and difference of two numbers are 20 and 8 respectively, then the difference of their square is: 12 180 28 160 12 180 28 160 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the numbers be x and y. Then, x + y = 20 and x - y = 8x2 - y2 = (x + y)(x - y) = 20 * 8 = 160.
Number System 728.038 x 54.978 - 72.016 x 85.250 = ? 43900 53900 33900 23900 43900 53900 33900 23900 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP ? = 728 x 55 - 72 x 85.25 = 40040 - 6138 = 339900
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