Question

Which term of the progression 4 + 8 + 12 + ... is 76?

Answer 1

a = 4

d = 8 − 4

d = 4

a_n = 76

a_n = a + (n − 1)d

76 = 4 + (n − 1)4

76 = 4 + 4n − 4

76 = 4n

n = `76/4`

n = 19