Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:
What is the number of digits in the number (1024) ${ }^{4}$ $\times(125)^{11}$ ?
(a)35
(b)36
(c)37
(d)38
Answer
Answer (as printed): B
Explanation
$(1024)^{4} \times(125)^{11}=\left(2^{10}\right)^{4} \times\left(5^{3}\right)^{11}=2^{40} \times 5^{33}=2^{7} \times\left(2^{33} \times\right.$ $\left.5^{33}\right)=2^{7} \times 10^{33}=128 \times 10^{33}$. Clearly, the number has $1,2,8$ and thirty-three zeros, i.e. $(3+33)=36$ digits in all.
Explanation as extracted from the printed page; notation may be imperfect.