Thirty students took a history test. The grouped frequency distribution of their scores is shown below. | Score | Frequency | |---|---| | 61 to 70 | 4 | | 71 to 80 | 10 | | 81 to 90 | 10 | | 91 to 100 | 6 | How many students scored **81 or higher**?

Add the frequencies of the bands at or above 81: $\text{81 to 90}: 10 \quad+\quad \text{91 to 100}: 6 \quad=\quad 16$. - Trap A ($6$) only picks the top band. - Trap B ($10$) only picks the second-highest band. - Trap C ($14$) likely comes from $4 + 10$ — picking the wrong two bands.