Sabrina, to find which fits, plug them in. Since 20% is closer to 15% than 30%, we know that more 15% is used than 30%.
3(.15) + 2(.3) = 5(.2)
.45 + .6 = 1
Nope
(10/3)(.15) + (5/3)(.3) = 5(.2)
.5 + .5 = 1
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