If Simon paid 25 cents for each orange and 15 cents for each mango, then how many oranges did Simon buy?
1) Simon spent a total of $1.55 on his purchase of mango and oranges.
2) Simon bought fewer mango than oranges.
From F.S 1, we know that 0.25*o+0.15*m = 1.55 \to 5o+3m = 31
We get integral solutions for o=2,m=7 and for o=5,m=2. Insufficient.
F.S 2 is clearly Insufficient.
Both taken together, we know that m<o. Thus, the no of oranges bought = 5.Sufficient.
All that is equal and not-Deep Dive In-equality
Hit and Trial for Integral Solutions