Question #1

Question

50 students total.
12 students travelled by car only
7 students travelled by bus only
5 students travelled by car and walked,but did not use a bus
10 students travelled by bus and walked,but did not use a car
3 students used all three forms of travel

I drew a Venn diagram.

Two students are chosen at random from all 50 students.

- Find the probability that
a) Both students walked
b) only one of the students walked

Question #2
What does (dA)/(dr) mean in the surface area of cylinder the problem?

Answer 1

I too made a Venn diagram and after filling in the given information , found two missing sections
1. Those that only walked
2. Those that took the bus or the car, but did not walk

confirm this please

#2, dA/dr means the rate of change of the surface area with respect to the radius.