✓ Question 14: 3
A snail climbs 3 m per day in a 10 m well and slips back 2 m at night. How many days does it take to get out?
Why, in question 14: If 3 cats catch 3 mice in 3 minutes, how many cats catch 100 mice in 100 minutes?
The answer is 3. Each cat catches 1 mouse every 3 minutes, so the 3 cats together catch 1 mouse per minute. In 100 minutes, they catch 100 mice.
How much does each one do
The temptation is to answer 100, because the 3 repeats three times in the statement. But the time has also changed, from 3 to 100 minutes, and that changes the calculation.
The safe way is to figure out how much one cat does on its own. If 3 cats catch 3 mice in 3 minutes, each cat catches 1 mouse in those 3 minutes.
The option 33 came from dividing 100 by 3, which is close to the number of mice each cat catches in the whole time, and not the number of cats.
Work and time problems appear in exams and competitions with taps filling tanks or people painting walls. The technique is always the same: calculate each one's rate and then add them together.
