Percentages are ratios of an amount compared to 100. The percent change of an old to new value is equal to 100% x \({ new - old \over old }\).
Betty scored 78% on her final exam. If each question was worth 4 points and there were 400 possible points on the exam, how many questions did Betty answer correctly?
| 64 | |
| 69 | |
| 78 | |
| 79 |