Respuesta :

Answer:

64

Step-by-step explanation:

Un=a+(n-1)d

given that Un is the number of terms which we're looking for

Un=1+(22-1)3

Un=1+(21)3

Un=1+63

Un=64

Answer:

Step-by-step explanation:

a1=1 a2=4 for every one, you add a 3 so 3*21=63 63+1=64 and that's the answer