Question
Introduction
This question
involves money and looks rather challenging, because there are a few unknown
quantities. To solve it, we use the
concept of unit costs, so that we can make an “apples-to-apples” ... er ... I
mean “pears-to-apples” J comparison of the prices.
Solution
Since
absolute dollar amounts are given, we can quickly solve [H11. Solve part of the problem] for the total costs of pears
and apples as follows [H02. Use a diagram / model]:-
Now we know
that the total cost (in dollars) of pears is 45 and for the apples it is 50 (5
more than 45). Although we do not know
the absolute numbers of pears and apples, we know their ratio. So let us write these down as, say, ‘square’
units.
Dividing
the total costs by the numbers gives the unit costs, which we know only in
ratio terms. So let us use, say,
‘circle’ units to denote these. But we
know that the unit cost (in $) of an apple is 0.50 less than that of a pear. And that is equivalent to 5 ‘circle’ units. From here [H05.
Work backwards], we quickly work out the cost of a pear (15 ‘circle’
units) as $1.50.
H02. Use a diagram / model
H05. Work backwards
H11. Solve part of the problem
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