In a school, 0.9 of the boys and 0.1 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 1230 children take part in charity work, how many less children 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 |
9x9 |
1x9 |
1 |
9 |
|
1x9 |
|
1x9 |
81 u |
9 u |
1 u |
9 u |
0.9 =
910 Boys that take part : Boys that do not take part = 9 : 1
0.1 =
110 Girls that take part : Girls that do not take part = 1 : 9
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 9 is 9.
Number of children who take part in charity work
= 81 u + 1 u
= 82 u
82 u = 1230
1 u = 1230 ÷ 82 = 15
Number of children who do not take part in charity work
= 9 u + 9 u
= 18 u
Number of less children who do not take part in charity work than those who take part in charity work
= 82 u - 18 u
= 64 u
= 64 x 15
= 960
Answer(s): 960