Thinking Skills: Critical Thinking and Problem Solving

100 Unit 3 Problem solving: basic skills

Therefore, the minimum distance is 59 km.

If you were particularly astute, you

would have noticed that the routes come in

three pairs of the same distance (e.g. PQRSP

is the reverse of PSRQP so must be the same).

This would have saved you half the

calculations.

Summary

•   We have learned that some problems

require a search to produce a solution.

•   We have seen the importance of being

systematic with a search, in order both to

ensure that the correct answer is obtained

and to be certain that we have the right

answer.

•   We also saw that searches do not always

have to be exhaustive and how analysis

of the problem can reduce the size of the

search and time taken.

yourself that it is never worth retracing your

steps) are:

PQRSP

PQSRP

PRQSP

PRSQP

PSRQP

PSQRP

This gives six values. In order to see how they

are obtained you may note that there are three

pairs, each pair visiting a different one of the

towns first (after leaving Picton). The two

routes in each pair take the last two towns in

opposite orders.

The distances associated with each route

are as follows:

59 km

62 km

67 km

62 km

59 km

67 km

Additional adult $10

Family ticket (for 1 adult and 2

children)

$20

Additional child 4–16 or senior

citizen

$5

Additional adult $10

Maria is taking her three children aged

3, 7 and 10 and two friends of the older

children (of the same ages) as well as her

mother, who is a pensioner. What is the

least it will cost them?

1    The notice below shows admission prices

to the Tooney Tracks theme park.

Adult $12

Child (aged 4–16) $6

Child (aged under 4) Free

Senior citizen $8

Family ticket (for 2 adults and

2 children)

$30

Additional child 4–16 or senior

citizen

$5

End-of-chapter assignments