Sorry to interrupt this convo , but I disagree about the Veritas Prep
book for Combinatorics and Probability . It is simply way too dense , there's no need to go so deep into this topic because :
1.It'll take you ages to do that book inside out and that time can be better spent on doing topics such as number properties and algebra more throughly ( Because these subjects are more frequently tested )
2.You might not see more than 1-2 problems on this topic on test day . I feel if you can handle the questions in the MGMAT guides
for probability you should be fine .
Again if you have like 6-7 months of time to prepare then go for the Veritas Prep
book . But like most people here if you are in a time crunch , then just stick to the level of complexity that MGMAT offers . Posted from GMAT ToolKit