A decimal number is of the form 3 b .0276, where b represents a digit. The decimal is then written in the form of the simplest fraction. The prime factorisation of the denominator of the fraction is 2 2 × 5 4 × 7 x , where x is a non-negative integer.
It is known that a rational number p/q has a terminating decimal expansion, if q can be prime factorised in the form 2n5m, where n and m are non-negative integers. Therefore, prime factorisation of the denominator of the simplest fraction equivalent to the number 3b.0276 is of the form 2n5m, where n and m are non-negative integers. It is given that prime factorisation of the denominator of the simplest equivalent fraction is 2^2 x 5^4 x 7^x ∴ 2n5m = 22 x 54 x 7x ⇒ 7x = 1 ⇒ x = 0 Thus, the value of x is 0.