Question 1030256
If you want to end up with 1 kg, and
the ratio is 7:3, then you want the 
weights to be:
{{{ .7 }}} kg of the k650/kg tea
{{{ .3 }}} kg of the k720/kg tea
( since 7: 3 = .7/.3 )
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{{{ .7*650 + .3*720 = 455 + 216 }}}
{{{ 455 + 216 = 671 }}}
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1 kg of blended tea costs k671