Question:
A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is:
[A].18
24
42
81
A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is:
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
| Let the ten’s and unit digit be x and | 8 | respectively. |
| x |
| Then, | 10x + | 8 | + 18 = 10 x | 8 | + x | ||
| x | x |
10×2 + 8 + 18x = 80 + x2
9×2 + 18x – 72 = 0
x2 + 2x – 8 = 0
(x + 4)(x – 2) = 0
x = 2.