There are two boxes of markers.The first box has only red

well i don't think probability greater than or equal to 30% is possible. the maximum that we can get is 27.2% . This case is possible if we assume that one of the box contains only 1 marker which is yellow and the other box contains 11 marker out of which 3 are yellow. then the required probability will be (1).(3/11)=27.2%

Actually it is in the question that Ist box has 3 types of markers. So atleast 3 are going to be there. But anywayz the probability is not exceeding 30% for those cases

How do we actually solve this question with statement 2? LCM 35?

I don't know which source you are using but the questions are very low quality.
For example, statement 1 does not clarify whether we are talking about box 1, box 2 or combined.
Statement 2 does not clarify that the probability of selecting 1 red or orange marker from box 1 is 3/5 or the probability of selecting 1 red or orange marker from both boxes combined is 3/5 Same for green/blue marker.
Also, I think data in the two statements contradicts. Say stmnt 2 has given combined boxes probability. Say there are 35 total markers.
P(Red/ORange) = 3/5 = 21/35
P(Green or Blue) = 2/7 = 10/35
So you have 4 yellow markers out of total 35 markers! I don't know how they get 4 out of 12 in stmnt 1.
If you look at them separately, again there is a problem
P(Red/Orange) = 3/5 so out of 5 total markers in box 1, 2 are yellow
P(Green/Blue) = 2/7 so out of 7 total markers in box 2, 5 are yellow
So 7 total yellow markers out of 12 total markers in both boxes combined!

My suggestion will be to use a quality GMAT question source.

Hi Karishma,

For statement 2- it is that probability of getting red or orange from box 1 and green or blue from box 2.
Hence it will provide us the info for selecting yellow from both boxes.

But for statement 1- we will get probability to select 4 out of 12 total markers less than 30% r8 for any combination ?