jawab guys sisa ini doang nih

jawab

n1 = 32
x1 = 6,3
n2 = 8
x2 = 7,3

rata sekarang   = xs

xs = n1 x1+ n2 x2 / (n1 + n2)

xs =32(6,3) + 8(7,3) /(32+8)

xs = (201,6 + 58,4) / (40)

xs = 260/40

xs= 6,5


2)

4 + 7 + 10 + ...+ 121 
a= 4
b = 3
un = 3n + 1 = 121
3n = 120
n = 40

sn = n/2 { a + un}
s40 = 40/2 ( 4+ 121)
s40 = 20(125)
s40 = 2500

32 =6,3
jumlah = 32 x 6,3 =201,6

8=7,3
jumlah =8 x 7,3 =58,4

rata sekarang = ( 201,6+56,4 )  : 40 =260/40 = 6,5

jawab.B