annamo137 annamo137

20-01-2015
Mathematics

Answered

A teacher had 21 red pens. If the ratio of red pens to blue pens she owned was 3:1, how many pens did she have total?

Answer :

konrad509 konrad509

20-01-2015

x - blue pens

[tex]\dfrac{21}{x}=\dfrac{3}{1}\\ 3x=21\\ x=7\\\\ 21+7=28[/tex]

28 in total

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