What is the sum of two numbers?
I. The bigger of these two numbers is 6 more than the smaller number.
II. 40% of the smaller number is equal to 30% of the bigger number.
III. The ratio between half of the bigger number and one-third of the smaller number is 2 : 1
Only II and III are sufficient
Only I and II are sufficient
I and either II or III is sufficient
All, II and III together are sufficient