Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:
The sum of digits of a two - digit number is 12 and the difference between the two - digits of the two - digit number is 6. What is the two - digit number? [IBPS-RRB Office Assistant (Online) Exam, 2015]
(a)39
(b)84
(c)93
(d)Other than the given options
(e)75
Answer
Answer (as printed): D
Explanation
Let the two - digit number be $10 a+b$ where $a>b$ According to the question, $$\begin{aligned} & a+b=12 \\ & a-b=6 \ldots \end{aligned}$$ On adding equation (i) and (ii). $$\begin{aligned} & 2 a=19 \\ & \Rightarrow a=9 \end{aligned}$$ From equation (i), $$\begin{aligned} & 9+b=12 \\ & \Rightarrow b=12-9=3 \end{aligned}$$ ∴ Number is $10 a+b$ $$=9 \times 10+3=93$$ ∴ When $a<b$. Then required number is = 39
Explanation as extracted from the printed page; notation may be imperfect.