very hard DS. Help me pls

[tanviet]

I do not know how to solve yes-no quesion like this

Leo can buy a certain computer for p1 dolar in state A, where tax is t1 percent, or he can buy the same computer for p2 dollars in State B, where the sales tax is t2. Is the total cost of the computer greater in State A than in State B?

a,t1>t2
b,p1t1>p2t2

[italian7745]

IMO E

Case a)

Let price of both computers be p1= 100 dollars and p2= dollars ...

Let t1=10 % t2= 5 %
So Cost of computer in state A > Cost of computer in state B

Now , if p1= 100 and p2 = 200

T1= 10% T2 = 5%

So, cost of computer in state B > Cost of computer in State A

Case b

P1 T1 > P2 T2

Let p1= 100 t1 = 5 500 > 400
p2 = 200 t2 = 2

Cost of computer State B > Cost of computer in state A

Let p1=200 t1=3
Let P2 = 100 t2 = 2

600>200

So Cost of computer State A > Cost of computer in state B

So, insufficient

Now lets combine

t1 > t2

p1t1 > p2t2

in the above examples we have taken these 2 cases already...

So E