Question 942145
{{{ a }}} = number of blue pens
{{{ b }}} = number of black pens
{{{ c }}} = number of red pend
{{{ d }}} = number of green pens
{{{ e = a + b + c + d }}}
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{{{ ( 2/5)*e = a }}}
{{{ (1/6)*(3/5)*e = b }}}
{{{ c = a + 12 }}}
{{{ c = (2/5)*e + 12 }}}
{{{ d = 24 }}}
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{{{ e = a + b + c + d }}}
{{{ e = ( 2/5)*e + (1/10)*e + (2/5)*e + 12 + 24 }}}
{{{ e - (9/10)*e = 36 }}}
{{{ (1/10)*e = 36 }}}
{{{ e = 360 }}}
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{{{ ( 2/5)*e = a }}}
{{{ a = (2/5)*360 }}}
{{{ a = 144 }}}
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{{{ b = (1/10)*e }}}
{{{ b = 36 }}}
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{{{ c = a + 12 }}}
{{{ c = 144 + 12 }}}
{{{ c = 156 }}}
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Greg has 156 red pens and 144 blue pens
He has 360 pens altogether
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check:
{{{ e = a + b + c + d }}}
{{{ 360 = 144 + 36 + 156 + 24 }}}
{{{ 360 = 360 }}}
OK