Paper 1 · Mathematical Reasoning and Aptitude
Three planets take 200, 250 and 300 days respectively for one revolution around the Sun. After how many days will they all come back to the same relative position?
AAfter 2800 days
BAfter 3000 days ✓ Correct
CAfter 3050 days
DAfter 3200 days
Correct answer: (B) After 3000 days — They meet again after 3000 days, so that is the answer.
Explanation
★They meet again after 3000 days, so that is the answer.
★They return to the same relative position after the least common multiple of their periods.
★The periods are 200, 250 and 300 days.
★Breaking these into prime factors and taking the highest powers gives the least common multiple.
★That least common multiple works out to 3000.
★So after 3000 days they all come to the same relative position.
Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.
Shared by Mcqkart · via Mcqkart.in