9514 1404 393
Answer:
4.5 lb
Step-by-step explanation:
The ingredients are proportional so ...
wheat/rice = 3/2 = ??/3 lb
Multiplying by 3 lb gives ...
?? = (3 lb)(3/2) = 9/2 lb = 4.5 lb
The mixture contains 4.5 lb of wheat.
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Additional comment
Writing the proportion with the unknown in the numerator makes it possible to find the solution in one step (multiply by the denominator). Any proportion can be written 4 different ways, so you can always choose one that makes the solution easy. (upside down and sideways)
a/b = c/d ⇔ b/a = d/c ⇔ a/c = b/d ⇔ c/a = d/b
