1. Diketahui suatu derat aritmatika 24 + 27 + 30 + 33 + ……

Jawaban:

1. a = 24 dan b = 3

2. U15 = a + (n – 1)b

= 24 + (15 – 1)3

= 24 + 14(3) = 24 + 42

=66

3. S15 = 15/2 (24 + 66)

= 15/2 (90)

=15 x 45

=675

a. a = 24 b = 3

b. U15 = 66

c. S15 = 675

Penjelasan dengan langkah-langkah:

Diket = 24,27,30,33, …

Ditanya = a. a dan b?

b. U15?

c. S15

Jawab = a. a = 24

b = 3

b. U15 = 24+(15-1)3

= 24+14.3

= 24+42 = 66

c. S15 = n/2(a+Un)

= 15/2(24+66)

= 7,5(90) = 675

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