Problem Solving

At a certain bookstore, each notepad costs x dollars and each markers costs y dollars. If $10 is enough to buy 5 notepads and 3 markers, is $10 enough to buy 4 notepads and 4 markers instead?

1). each notepad cost less than $1

2). $10 is enough to buy 11 notepads

OA-E

My Approach :

Given : 5x +3y <10
to find : 4x + 4y <10
= 4(x +y) <10

1. x<1(Insuff)
2. 10y< 11 => y< 1.1

Now combine both

We take the max possible value i.e x=1(although equality does not exists,but just for the sake of easy calculations)

and max of y from (2) => y=1.1

Now put this in the expression :
4(x + y) = 4*(1 +1.1) = 4*2.1 = 8.4 <10

so even if we take both the max value of x and y, we still have sufficient money to buy 4x and 4y within $10
so IMO-C

This is a GMAT Prep Question. So the OA is correct. Please tell me where am I wrong.

Thanks