Number System A basket contains 5 blue, 4 green and 3 red ball. If three balls are picked at random, what is the probability that at least one is red ? 37/52 32/51 31/58 34/55 37/52 32/51 31/58 34/55 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Probability of having no red ball is9C3 / 12C3 = 21/55Probability of having at least one red ball is 1 - 21/55 = 34/55
Number System 20% of the total number of students in a school play football. How many students do not play football if the total number of students in the school is 7600 ? 6080 6000 5800 5976 6080 6000 5800 5976 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 20% of 7600 = 1520Therefore, students who do not play football = 7600 - 1520 = 6080
Number System The digit in unit's place of a three digit number is thrice the digit in ten's place & the digit in hundred's place is two-third of the digit in ten's place. If the sum of three digits of number is 14 211 239 221 215 211 239 221 215 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Let the ten's digit be x.∴ Unit's digit = 3xHundered's digit = 2x/3∴ x + 3x + 2x/3 = 14= 3x + 9x + 2x = 14 x 3= 14x = 14 x 3= x = 3∴ Number = 239
Number System If a + b = 16 and ab = 68, what is the value of a² + b² ? 112 120 124 116 112 120 124 116 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP a + b = 16 Therefore, (a+b)² = (16)² = 256 a² + b² + 2ab = 256Therefore, a² + b² = 256 - 2 x 68Therefore, a² + b² = 256 - 136 = 120
Number System In how many different ways can the letters of the word 'DETERMINE' be arranged ? 63480 60480 61480 62480 63480 60480 61480 62480 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP No. of arrangements = 9! / 3! Because, E comes 3 times = 60480
Number System 4550 ÷ 25% of ? = 130 140 130 125 135 140 130 125 135 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP 4550 ÷ ? x 25/100 = 130= 4550 ÷ ?/4 = 130= 4550 x 4/? = 130= ? x 130 = 4550 x 4= ? = 4550 x 4/130 = 140
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