Question 21
Of the staff in an office, 15 rode a pushbike to work on Monday, 12 rode on Tuesday and 9 rode on Wednesday.
If 22 staff rode a pushbike to work at least once during these three days, what is the maximum number of staff who could have ridden a pushbike to work on all three days?
If 22 staff rode a pushbike to work at least once during these three days, what is the maximum number of staff who could have ridden a pushbike to work on all three days?