Does this make sense?
1. to scale up the ratio of 30 boys to 48 girls you need to multiply. the two equivalent ratios i scaled were 60: 96 and 180: 288 boys to girls.
ex: 30/48*2=60/96
ex: 60/96*3=180/288
2. to scale down the ratio of 30 boys to 48 girls you need to divide. the two equivalent ratios i scaled were 30: 48 and 10: 16 boys to girls.
ex: 60/24/2=30/48
ex: 30/48/3=10/16