Answer: The first term of the sequence is 2.2
Step-by-step explanation: 
Let g1 be x, 
so that g2 will be
g2 = 1 + 2x
And g3 will be
g3 = 1 + 2(1 +2x)
 = 1 + 2 + 4x
 =3 + 4x
And g4 will be 
g4 = 1 + 2(3+4x)
 = 1 + 6 + 8x
 = 7 + 8x
If g2 + g4 = 30,
Therefore 1 + 2x + 7 + 8x = 30
8 + 10x = 30
10x = 30 - 8
10x = 22
X= 22/10
X= 2.2
Since x = g1,
Therefore g1 is 2.2