What is the value of \(5+4\cdot 5+4\cdot 5^2+4\cdot 5^3+4\cdot 5^4+4\cdot 5^5?\)
A. \(5^6\)
B. \(5^7\)
C. \(5^8\)
D. \(5^9\)
E. \(5^{10}\)
Answer: A
Source: GMAT Club Tests
What is the value of \(5+4\cdot 5+4\cdot 5^2+4\cdot 5^3+4\cdot 5^4+4\cdot 5^5?\)
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You can also replace "4" with "5 - 1", so the expression becomesGmat_mission wrote: ↑Sun Nov 28, 2021 6:51 amWhat is the value of \(5+4\cdot 5+4\cdot 5^2+4\cdot 5^3+4\cdot 5^4+4\cdot 5^5?\)
5 + (5-1)*5 + (5-1)*5^2 + (5-1)*5^3 + (5-1)*5^4 + (5-1)*5^5
= 5 - 5 + 5^2 - 5^2 + 5^3 - 5^3 + 5^4 - 5^4 + 5^5 - 5^5 + 5^6
= 5^6
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