S = 1 + 3 + 5 + ... + 11 + 13 + 15
S = 15 + 13 + 11 + ... + 5 + 3 + 1
==> 2S = (1 + 15) + (3 + 13) + (5 + 11) + ... + (15 + 1)
There are 8 terms in the sum, so
2S = 8 * 16 = 128
S = 128/2 = 64
Answer:
1:2
Step-by-step explanation:
because only one gets into the team
and the remaining two don't make the team
a-9=20
a=20+9
a=29
b-9>20
b>29