Let the regular price at store L is 100L & at store M is 100M

1) Discounted price at L = 90L

Discounted price at store M = 85M

But still we don't the respective value of L & M --->Insufficient

2) Discounted price at L = 100L - 5

Discounted price at M = 100M - 6

But still we don't the respective value of L & M --->Insufficient

1+2) 10L = 5 & 15M = 6

We can get the respective value of L & M --->Sufficient

Answer C

_________________

If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS.

Kudos always maximizes GMATCLUB worth -Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply