PSLE In a school, 40% of the members in Reading Club and 75% of the members in Computer Club are girls. Both clubs have the same number of boys. The Computer Club has 77 more girls than the Reading Club. How many girls are there altogether?
|
Reading Club |
Computer Club |
Types |
Girls |
Boys |
Girls |
Boys |
Comparing the girls and the boys in each club |
2x1 |
3x1 |
3x3 |
1x3 |
Comparing the boys in 2 clubs |
|
1 |
|
1 |
|
2 u |
3 u |
9 u |
3 u |
40% =
40100 =
25 Fraction of the members in Reading Club that are boys
= 1 -
25 =
35 75% =
75100 =
34 Fraction of the members in Computer club that are boys
= 1 -
34 =
14 The number of boys in both clubs is the same. Make the numerators the same. LCM of 3 and 1 is 3.
3x15x1 of the members in Reading Club =
1x34x3 of the members in Computer Club
35of the members in Reading Club =
312 of the members in Computer Club
Number of more girls in Computer Club than Reading Club
= 9 u - 2 u
= 7 u
7 u = 77
1 u = 77 ÷ 7 = 11
Total number of girls
= 2 u + 9 u
= 11 u
= 11 x 11
= 121
Answer(s): 121