The probability of rolling an even number on a six sided die is 1/3.
Answer:
a₁ = 10
Step-by-step explanation:
The common difference d is calculated as
d = a₃ - a₂ = - 20 - (- 5) = - 20 + 5 = - 15
Then
a₂ - a₁ = d , that is
- 5 - a₁ = - 15 ( add 5 to both sides )
- a₁ = - 10 ( multiply both sides by - 1 )
a₁ = 10
