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? 18 13 7 15 18 13 7 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 In how many different ways can the letters of word 'BIOLOGY' be arranged ? 2678 2520 2410 2367 2678 2520 2410 2367 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In BIOLOGY total 7 letters are there but O comes twice.∴ Number of arrangements = 7!/2! = 2520
Number System A number consists of 3 digit whose sum is 10. The middle digit is equal to the sum of the other two and the number will be increased by 99 if its digits are reversed. The number is: 253 370 145 352 253 370 145 352 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the middle digit be x. Then, 2x = 10 or x = 5.So, the number is either 253 or 352. Since the number increases on reversing the digits, so the hundred's digit is smaller than the unit's digit. Hence, required number = 253.
Number System A certain number successively divided by 2, 5 and 7 leaves remainders 1, 2 and 3 respectively. When the same number is divided by 70, what is the remainder? 36 34 33 35 36 34 33 35 ANSWER DOWNLOAD EXAMIANS APP
Number System Supply the missing figure : 3, 11, 8, 16, 13 .... 18 28 12 18 21 28 12 18 21 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 21
Number System The difference between a positive proper fraction and its reciprocal is 9/20. The fraction is: 3/5 5/4 3/10 4/5 3/5 5/4 3/10 4/5 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
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