On thursday 30 students went to afterschool tutoring on friday six students went what is the percent decrease in the number of students who went to tutoring
a. 20%
b. 80%
c. 400%
d. 500%
i know the answer is b. but here is the question i need with.
brittany chose a as the correct answer. how did she get this answer?
and

Atrucker had a load of grain containing 2 tons. she unloaded 1 ton and 1,200 pounds at the warehouse. how much grain does she still have left on the truck?

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =