Answer: C) 90 Explanation: The given number series follows a pattern that, 56 56 + 8 = 64 64 - 16 = 48 48 + 32 = 80 (Not equal to 90) 80 - 64 = 16 16 + 128 = 144    Hence, the odd number in the given number series is 90.

Answer: C) 0.375 Explanation: Expressing 3/8 as a decimal fraction: We can convert 3/8 into a decimal fraction by just dividing 3 by 8 or making 3 into 8 parts. Then, it is 3/8 = 0.375 as a decimal fraction.   Other Method:: 3/8 as a Decimal : In this we should convert the denominator into 10, 100, 1000, 10000, 100000,... to make it simple. Now to make 8 into 1000, we multiply numerator and denominator with 125   => (3 x 125)/(8 x 125) = 375/1000 = 0.375.

Answer: D) 10 Explanation: Let Rajeev's present age be  x years. Rajeev's age after 15 years = (x + 15) years. Rajeev's age 5 years back = (x - 5) years Then ATQ,  x + 15 = 5 (x - 5) x + 15 = 5x - 25 => x = 10   Hence, Rajeev's present age = x = 10 years.

Answer: C) 21 Explanation: A prime number is a whole number greater than 1 whose only factors are 1 and itself.   Factors of 5 are 1, 5 Factors of 11 are 1, 11 Factors of 21 are 1, 3, 7, 21 Factors of 37 are 1, 37.   Hence, according to the definition of a prime number, 21 is not a prime number as it has more than two factors.

Answer: C) 0.67 Explanation: To convert a fraction into decimal, just take the number on top which we called the numerator and divide it by the number at the bottom which we called the denominator. 2/3 How it comes : 2 ÷ 3 = 0 bring down the decimal point. 20 ÷ 3 = 6 and carry the remainder 2 to make 20 20 ÷ 3 = 6 and carry the remainder 2 to make 20 20 ÷ 3 = 6 and carry the remainder 2 to make 20 etc... This gives the recurring decimal 0.6666... If we round off to two decimals , then it becomes 0.67.   Hence, decimal fraction of 2/3 = 0.67.

Answer: A) 3.571 Explanation: Here we have 25 divided by 7. 25 will not go directly in 7 Hence, we get the result in decimals. 25/7 = 3.571.

Answer: A) 0.5 Explanation: In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.   Herein the given sequence, 4, 2, 1, 0.5, 0.25, 0.125,... Common Ratio r = 2/4 = 1/2 = 0.5/1 = 0.25/0.5 = 0.125/0.25 == 0.5.

Answer: A) 1 Explanation: The mutiplicative inverse of a number is nothing but a reciprocal of a number. Now, the product of a number and its multiplicative inverse is always equal to 1.   For example : Let the number be 15 Multiplicative inverse of 15 = 1/15 The product of a number and its multiplicative inverse is = 15 x 1/15 = 1.