BOX 3.11 Three Solutions to the Best-Buy Problem

Which is the best buy for barbecue sauce?

Percentage Using Strategy

Difference strategy

Simulation study

Supermarket study


18−14=4 ounces

79−81=−2 cents

A gives 4 more

bunces and costs 2

cents less than B



Which is the best buy for sunflower seeds?


Unit-price strategy

30/3=10 cents per ounce

44/4=11 cents per ounce

A costs less per ounce than B




Which is the best buy for peanuts?


Ratio strategy

2×45=90 cents

2×4=8 ounces

A costs twice as much

as B and contains more

than twice as much




SOURCE: Adapted from Lave (1988).

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