In a school, 0.8 of the boys and 0.7 of the girls take part in charity work. There is an equal number of girls and boys who do not take part in charity work. If 380 pupils take part in charity work, how many less pupils do not take part in charity work than those who take part in charity work?
Boys |
Girls |
Take part |
Do not take part |
Take part |
Do not take part |
4x3 |
1x3 |
7 |
3 |
|
1x3 |
|
1x3 |
12 u |
3 u |
7 u |
3 u |
0.8 =
45 Boys that take part : Boys that do not take part = 4 : 1
0.7 =
710 Girls that take part : Girls that do not take part = 7 : 3
The number of girls who do not take part is repeated. Make the number of girls who do not take part the same. LCM of 1 and 3 is 3.
Number of pupils who take part in charity work
= 12 u + 7 u
= 19 u
19 u = 380
1 u = 380 ÷ 19 = 20
Number of pupils who do not take part in charity work
= 3 u + 3 u
= 6 u
Number of less pupils who do not take part in charity work than those who take part in charity work
= 19 u - 6 u
= 13 u
= 13 x 20
= 260
Answer(s): 260