PSLE In a school, 45% of the members in Reading Club and 50% of the members in Computer Club are girls. Both clubs have the same number of boys. The Computer Club has 20 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 |
9x1 |
11x1 |
1x11 |
1x11 |
Comparing the boys in 2 clubs |
|
1 |
|
1 |
|
9 u |
11 u |
11 u |
11 u |
45% =
45100 =
920 Fraction of the members in Reading Club that are boys
= 1 -
920 =
1120 50% =
50100 =
12 Fraction of the members in Computer club that are boys
= 1 -
12 =
12 The number of boys in both clubs is the same. Make the numerators the same. LCM of 11 and 1 is 11.
11x120x1 of the members in Reading Club =
1x112x11 of the members in Computer Club
1120of the members in Reading Club =
1122 of the members in Computer Club
Number of more girls in Computer Club than Reading Club
= 11 u - 9 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Total number of girls
= 9 u + 11 u
= 20 u
= 20 x 10
= 200
Answer(s): 200