Answer:
The first term is:
Step-by-step explanation:
The arithmetic sequence is defined by

where
is the first term
is the common difference
as
the 17th term of an arithmetic sequence is 51.
i.e. 
so

∵
,
, 
∵ 

Therefore, the first term is:
Answer:
D
Step-by-step explanation:
Ratio of girls : boys = 5 : 4
<u>Find total parts:</u>
Total parts = 5 + 4 = 9
<u>Find 1 part:</u>
9 parts = 36
1 part = 36 ÷ 9 = 4
<u>Find 5 parts (Girls):</u>
Girls = 5 parts = 4 x 5 = 20
Answer: There are 20 girls.
4 embroidered uniforms= $5 fee for each 4 embroidered uniform and $25 for each uniform. 5 x 4 = 20. 25 x 4 = 100. 100 + 20= 125. He paid $120 for the embroidered uniform.