Question

Which term of the progression `3/4 + 1 + 5/4 + ...` is 12?

Answer 1

a = `3/4`

d = `1 − 3/4 = 1/4`

d = `5/4 - 1 = 1/4`

d = `1/4`

a_n = 12

a_n = a + (n − 1)d

`12 = 3/4 + (n − 1)1/4`

Multiply the entire equation by 4 to clear the fractions:

48 = 3 + (n − 1)

48 = 3 + n − 1

48 = 2 + n

48 − 2 = n

n = 46