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Ashley save ₱50 on the first week, ₱100 on the second week, ₱200 in the third week. how much money will she have on the 8th week?
A.₱800
B.₱1,600
C.₱3,200
D.₱6,400

Freya saves an amount in his coin bank every week. To make saving a fun activity, she doubles whatever amount is inside the coin bank. On the first week, she saves 1 peso. How much money will there be in the coin bank after the 12th week?

A.₱4095
B.₱1023
C.₱120
D.₱78




Sagot :

Answer:

1. D. ₱6,400

2. A. ₱4095

Step-by-step explanation:

1.

aₙ= a₁ • rⁿ⁻¹

a₁ = 50

r = 2

n = 8

a₈ = 50 • 2⁸⁻¹

= 50 • 128

a₈ = 6400

2.

Sₙ = a(1 - rⁿ) / 1 - r

a = 1

r = 2

n = 12

S₁₂ = 1(1 - 2¹²) / 1 - 2

= (1 - 4096) / -1

= -4095/-1

S₁₂ = 4095