I also got A but for the denominator, why did you use (20+12+10) instead of (30+18+10)? I got that 7/58 was still greater than 10%
Bunuel
Every item in an apparel shop has a tag that is either blue, green or yellow in color. The items with a blue tag are priced between $20 and $30. The items with a green tag are priced between $12 and $18 and the items with a yellow tag are priced between $5 and $10. Mary buys three items, each with a different color tag. Is the total discount on three items greater than 10%?
(1) The discount on the items with a blue tag is 20% and that on the items with a green tag is 25%.
The least discount on a blue-tagged item = 20*0.2 = $4;
The least discount on a green-tagged item = 12*0.25 = $3;
Even if Mary bought an yellow-tagged item at the full price of $10, the discount = (4 + 3)/(20 + 12 + 10)= 7/42 = 1/6 > 10%. Sufficient.
(2) The discount on the items with a yellow tag is 40%.
If Mary bought a blue-tagged item and a green-tagged item with 100% discount, then the overall discount would be more than 10%.
If Mary bought a blue-tagged item and a green-tagged item with 0% discount and an yellow-tagged item with 40% discount, then the overall discount would be less than 10%.
Not sufficient.
Answer: A.
Hope it's clear.