Of getting less than 7: 100%
of getting a number greater than or equal to 3: 4/6 or 67%
When you compare 649 and 645, you see that the first two digits are the same, and you compare until the last digit: in a way you need to do 3 comparisons, one for each digit (and after first and second you conclude that you still need to compare).
when you compare 645 and 738 you see immediately that the second number is bigger: the numbers differ already in the number of hundreds than they have, so you don't need to compare their tenths and one's, just the hundreds.
Let x be the number of people at University B
x + (x+3.5) = 9.5
2x +3.5 = 9.5
2x = 6
x = 3 million students at University B
x + 3.5 = 3 + 3.5 = 6.5 million students at University A
First you have to subtract 510-60=450
second divide 450 by 2 = 225
and you have the answer 225