Multiple choice

Sangeeta remembers that her father's birthday was certainly after eighth but before thirteenth of December. Her sister Natasha remembers that their father's birthday was definitely after ninth but before fourteenth of December. On which date of December was their father's birthday?

  1. 10th

  2. 11th

  3. 12th

  4. Data inadequate

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sangeeta remembers the birthday is after December 8th but before 13th (so 9th, 10th, 11th, or 12th). Natasha remembers it is after December 9th but before 14th (so 10th, 11th, 12th, or 13th). The common dates are 10th, 11th, and 12th. With three possible dates, the data is inadequate.