PSLE
The students at a sports meet are divided in Team A and Team B. The ratio of the number of boys to girls in Team A is 5 : 4. The ratio of the number of boys to girls in Team B is 5 : 1. There are 2 times as many students in Team B as in Team A. There are 30 less boys in Team A than Team B. What is the total number of students in Team A?

Team A		Team B
9 u		6x3 = 18 u
Boys	Girls	Boys	Girls
5 u	4 u	5x3 = 15 u	1x3 = 3 u

Total number of students in Team A
= 5 u + 4 u
= 9 u

Total number of students in Team B
= 2 x 9 u
= 18 u

The total number of students in Team B is repeated.
Use LCM to make the total number of students in Team B the same.
LCM of 18 and 6 is 18.

Number of less boys in Team A than Team B
= 15 u - 5 u
= 10 u

10 u = 30

1 u = 30 ÷ 10 = 3

Total number of students in Team A
= 5 u + 4 u
= 9 u
= 9 x 3
= 27

Answer(s): 27