Answer:
a₁ = 250
Explanation:
Use the given values in the formula for the sum of a geometric series, and solve for the unknown.
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S₆ = a₁×(1 -r⁶)/(1 -r) . . . . sum of 6 terms of a geometric series
922.32 = a₁×(1 -(4/5)⁶)/(1 -4/5) = a₁×5×(1 -4096/15625) = a₁×11529/3125
922.32×3125/11529 = a₁ = 250 . . . . divide by the coefficient of a₁