In a specific sequence, every term after the first is one less than double the preceding term. Given that the initial term is 1.25, what is the value of the 3rd term?

Correct answer marked below

−0.5

Correct

2.5

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Explanation

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Official Explanation

Official

Let N1 = 1.25. Then, N2 = 2(1.25) - 1 = 1.5. Next, N3 = 2(1.5) - 1 = 2.

Comments

NishatAug 23, 2024

Thank for sharing!!!

NominNov 4, 2024

thanks for posting

FranciscoAug 21

thanks, helpful!

AniketAug 18

is the "one less than double" always x*2 - 1 or could it be (x-1)*2? wording always makes me second guess myself

RanjeetAug 19

it's double first then subtract, so x*2 - 1. the (x-1)*2 reading is the trap.

What this question tests

Your ability to spot and extend arithmetic and geometric sequences and work with recursive definitions.

Off-by-one errors in indexing (a₀ vs a₁) or confusing an arithmetic difference with a geometric ratio.