Adding fractions with unlike denominators 1/3 + - 2/7

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?