Agroup of students is arranging squares into layers to create a project. the first layer has 5 squares. the second layer has 10 squares. which formula represents arithmetic explicit formula to determine the number of squares in each layer?
a. a1 = 5; an = 5 ⋅ an − 1, n > 0
b. a1 = 5; an = 5 ⋅ an + 1, n > 0
c. a1 = 5; an = 5 + an − 1, n > 0
d. a1 = 5; an = 5 + an + 1, n > 0