Answer:1) c. 5,9,13,17,21
2) a. a1=8, an=an-1 -2
Step-by-step explanation: 1) an=4n+1
⇒ a1=4×1+1=5
a2=4×2+1=9
a3=4×3+1=13
a4=4×4+1=17
a5=4×5+1=21
2) clearly a1=8 and then the terms of series are decreasing by 2
so, an=an-1 -2
19) B
20) D
21) A
22) B
23) C
24) C
Step-by-step explanation:
B = area of the base
= 9×4 = 36 square inches
P= perimeter of the base
= 2(9+4)
=2×13= 26 inches
H =distance between the bases
= 16 inches
SA= 2B+PH
= 2(36)+ 26× 16
= 72+416 = 488 square inches