PSLE In a school, 60% of the members in Reading Club and 90% of the members in Computer Club are boys. Both clubs have the same number of girls. The Computer Club has 120 more boys than the Reading Club. How many boys are there altogether?
|
Reading Club |
Computer Club |
Types |
Boys |
Girls |
Boys |
Girls |
Comparing the boys and the girls in each club |
3x1 |
2x1 |
9x2 |
1x2 |
Comparing the girls in 2 clubs |
|
1 |
|
1 |
|
3 u |
2 u |
18 u |
2 u |
60% =
60100 =
35 Fraction of the members in Reading Club that are girls
= 1 -
35 =
25 90% =
90100 =
910 Fraction of the members in Computer club that are girls
= 1 -
910 =
110 The number of girls in both clubs is the same. Make the numerators the same. LCM of 2 and 1 is 2.
2x15x1 of the members in Reading Club =
1x210x2 of the members in Computer Club
25of the members in Reading Club =
220 of the members in Computer Club
Number of more boys in Computer Club than Reading Club
= 18 u - 3 u
= 15 u
15 u = 120
1 u = 120 ÷ 15 = 8
Total number of boys
= 3 u + 18 u
= 21 u
= 21 x 8
= 168
Answer(s): 168