8 1-and-a-half blocks would be 12 blocks, and so 12/17, because 12 blocks in 17 mins., so you divide 12 by 17 to get ---- blocks per minute, which is 12/17 as a fraction, or approx. 0.705882353 blocks per minute.
2/3 + 1/4. You start by converting the fractions so that they have a common denominator.
8/12 + 3/12 = 11/12
11/12 of the girls have blue and brown eyes. That leaves 1/12 of the girls who have neither blue nor brown eyes.
