Question 1056491
day 1: {{{ 2^1 }}}
day 2: {{{ 2^1 + 2^2 }}}
day 3: {{{ 2^1 + 2^2 + 2^3 }}}
day 4: {{{ 2^1 + 2^2 + 2^3 + 2^4 }}}
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Doing the math:
day 1: {{{ 2 }}}
day 2: {{{ 2 + 4 = 6 }}}
day 3: {{{ 2 + 4 + 8 = 14 }}}
day 4: {{{ 2 + 4 + 8 + 16 = 30 }}}
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After {{{ n }}} days shw has saved {{{ 2^( n+1 ) - 2 }}} nickels
{{{ 2^( n+1 ) - 2 > 500 }}}
{{{ 2^( n+1 ) > 502 }}}
I can take the log base 10 of both sides
{{{ ( n + 1 )*log(2) > log( 502 ) }}}
{{{ n + 1 > log( 502 ) / log( 2 ) }}}
{{{ n + 1 > 2.7007 / .30103 }}}
{{{ n + 1 > 8.971 }}}
{{{ n > 7.971 }}}
It will take 8 days to save more than 500 nickels
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check:
{{{ 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256 = 510 }}}
Ok
By all means get another opinion, also