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1.

The sum of the first n terms of an arithmetic sequence is:

Sₙ = a(1 − rⁿ)/(1 − r)

Sₙ = (n/2)[2a + (n − 1)d]

Sₙ = n(a + d)

Sₙ = a/(1 − r)

2.

If a, b, c are in arithmetic sequence, then b equals:

√(ac)

(a + c)/2

2ac/(a + c)

a + c

3.

The sum of the first 10 terms of the geometric sequence 2, 6, 18, 54, … is:

59,048

59,049

19,682

118,096

4.

In an arithmetic sequence T₄ = 17 and T₁₀ = 41. The sum of its first 25 terms is:

1,250

1,325

1,300

1,375

5.

A ball dropped from a height of 20 m rebounds to 3/4 of its previous height after each bounce. Its height after the 5th bounce is about:

15 m

6.33 m

3.56 m

4.75 m

6.

The same ball is dropped from 20 m and rebounds to 3/4 of its height each time. The total distance it travels until it rests is:

140 m

80 m

120 m

160 m

Lesson 1 Questions: Arithmetic and Geometric Sequences and Series — Lesson quiz