It is biased because they surveyed people who were at a park, therefore they enjoy parks and would want more in the area
It could be a parallelogram because they too, have 2 sides that have one value and another two sides with a different value. a rhombus would work too.
It is 1595. Put it on excel so you can better have an overview how it is done. You need 5 columns, column A-E. On column A, put 1 to 5 in rows 1 to 5. On column C, put the answers: 2, 7, 26, 101 and 400. On column D, put number 3 in all 5 rows. Back on column B, insert =sum(C1-A1) on row 1 and copy till row 5. On column E, insert =sum(B1+C1*D1) on row 1 and copy till row 5 and you will get 1595 at the end.
Total number of possible outcomes = 6
Total number of outcomes with 3 or multiple of 3 = 2
They are 3 and 6
P(3 or multiple of 3) = 2/6 = 1/3
Answer : 1/3
C.
because a, b, and d aren't porportional
but c x is divided by 2