The table shows the grades that students received on a test what fraction of the students scored an a or b on the test

Okay. So, 15% is 15/100 and 33% is 33/100. 15 + 33 is 48. You leave the denominator the same, so the fraction is 48/100. However, the fraction needs to be simplified. Whatever you do to the numerator, we must do to the denominator. We can divide both numbers by 4 to get the simplified fraction form. 48/4 is 12. 100/4 is 25. There. The simplified fraction is 12/25. The answer is H: 12/25.

Hmmm i had this before , give me a sec