Question

The sum of the first 6 terms of a geometric series is 15,624 and the common ratio is 5 what is the first term of the serious?

Answer 1

Answer:

first term = 4

Step-by-step explanation:

Sₙ = (a₁ * (1 - rⁿ)) / (1 - r)     a₁: first term     r: common ratio     n: terms

15624 = (a₁ * (1 - 5⁶)) / (1 - 5)

          = (a₁ * -15624) / -4

a₁ x (-15624) =15624 x (-4)

a₁ = 4

check: 4+20+100+500+2500+12500 =15624