The table below shows the probability distribution of student ages in a high school with 1500 students. What is the expected value for the age of a randomly chosen student? Age: 13 14 15 16 17 18
Prob: 0.01 0.25 0.27 0.30 0.16 0.01

Ihave trouble finding the nth term of a linear sequence

Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?

Meee i honestly dont know what this question talking about