Final answer:
The percent increase in hourly pay is 3.33%.
Step-by-step explanation:
To calculate the percentage increase in hourly pay, we need to find the difference between the new pay rate and the original pay rate, and then divide it by the original pay rate. In this case, the researcher receives an 85 cent per hour raise after working six months. This means the original pay rate was $25.50 per hour and the new pay rate is $25.50 + $0.85 = $26.35 per hour.
The difference between the new pay rate and the original pay rate is $26.35 - $25.50 = $0.85. Dividing this difference by the original pay rate gives us $0.85 / $25.50 = 0.0333.
To express this as a percentage, we multiply the result by 100, so the percent increase in hourly pay is 0.0333 * 100 = 3.33%.