Number System Which one of the following represents the sum of the first n even numbers? N(N – 1) N(N + 1) N2+ 1 N2 N(N – 1) N(N + 1) N2+ 1 N2 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP N (N + 1)
Number System In a two-digit number, the digit in unit's place is two more than three times the digit in ten's place. If the sum of the two digits is 10, what is the number ? 18 22 28 24 18 22 28 24 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the number be 10x + y.∴ y = 3x + 2 .......(i)And, x + y = 10 ......(ii)From (i) and (ii), x = 2, y = 8∴ Number = 28
Number System What is the difference between the local value of 7 and 5 in the number 2574? 570 413 403 430 570 413 403 430 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 500 – 70 = 430
Number System How many times the keys of a typewriter have to be pressed in order to write first 400 counting numbers? 1082 1092 1192 1200 1082 1092 1192 1200 ANSWER DOWNLOAD EXAMIANS APP
Number System The difference between a positive proper fraction and its reciprocal is 9/20. The fraction is: 4/5 3/10 3/5 5/4 4/5 3/10 3/5 5/4 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 1/x - x = 9/20 20x2 + 9x - 20 = 0 20x2 + 25x - 16x - 20 = 0 5x(4x + 5) -4(4x + 5) = 0(4x + 5)(5x - 4) = 0x = 4/5
Number System Complete the series : 81, 69, 58, 48, 39 ........ 30 28 29 31 30 28 29 31 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 31
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