There are some pupils in the zoo.
310 of them are girls, of whom 70% of them do not wear watches.
47 of the boys do not wear watches. What is the percentage of the pupils in the zoo who wear watches?
Girls |
Boys |
Total |
3x10 = 30 u |
7x10 = 70 u |
10x10 = 100 u |
No watches |
Watches |
No watches |
Watches |
|
7x3 |
3x3 |
4x10 |
3x10 |
|
21 u |
9 u |
40 u |
30 u |
100 u |
70% =
70100=
710 The number of girls is the repeated identity. Make the number of girls the same. LCM of 3 and 10 is 30.
Number of pupils who wear watches
= 9 u + 30 u
= 39 u
Total number of pupils
= 21 u + 9 u + 40 u + 30 u
= 100 u
Percentage of the pupils in the zoo who wear watches
=
39100 x 100%
= 39%
Answer(s): 39%