a. 65 + 1 SD = 65 + 1.7 = 66.7 in
That means that there are: 100% - ( 50% + 34% ) = 100% - 84% = 16% students taller than 66.7 inches.
b. 13.5% + 34% + 13.5% + 34% = 95%
0.95 * 300 = 285
There are 285 students between the heights of 61.6 in and 68.7 in.