The ratio of two numbers is 3 : 4.  The product of LCM and HCF is 10800.  The sum of these numbers is?

180 210 225 240

210

A × B = LCM × HCF 3R × 4R = 10800 12R2 = 10800 R2 = 900 R = 30 A + B = (3 + 4) × 30 = 210