Standardized Test Practice

1
EXAMPLE 5
Standardized Test Practice
SOLUTION
a1 3 5(1) 8
Identify first term.
a20 3 5(20) 103
Identify last term.
Write rule for S20, substituting 8 for a1 and 103
for a20.
1110
Simplify.
2
EXAMPLE 6
Use an arithmetic sequence and series in real life
You are making a house of cards similar to the
one shown
3
EXAMPLE 6
Use an arithmetic sequence and series in real life
SOLUTION
an a1 (n 1) d
Write general rule.
3 (n 1)3
Substitute 3 for a1 and 3 for d.
3n
Simplify.
4
EXAMPLE 6
Use an arithmetic sequence and series in real life
SOLUTION
Find the sum of an arithmetic series with first
term a1 3 and last term a14 3(14) 42.
b.
5
for Examples 5 and 6
GUIDED PRACTICE
12
5. Find the sum of the arithmetic series
(2 7i).
i 1
6. WHAT IF? In Example 6, what is the total
number of cards if the house of cards has 8 rows?
ANSWER
108 cards