b did both
draw Venn diagram
fri---both- weekend
|20-b | b |29-b|
20-b + b + 29-b = 40
49 - b = 40
b = 9
11 fri , 9 both , 20 weekend
A survey carried out on 40 students about when they did their homework over the weekend
F=(homework done on friday)
S=(homework done on saturday/Sunday )
n(f)=20,n(s)=29
How many did both days ?
1 answer
1 answer