122 Unit 3 Problem solving: basic skills
2 Finn walks to school, a distance of 1.5 km
which takes him 15 minutes. His older
sister, Alice, cycles to school on the same
route at an average speed of 18 km/h.
She leaves home 5 minutes later than
Finn. Does she overtake him on the way
and, if so, where? At what time would she
have to leave to arrive at school at exactly
the same time as Finn?
3 A shop normally sells breakfast cereal for
$1.20 a packet. It is currently running a
promotion, so if you buy two packets, you
get a third free.
Tabulate and graph the price per packet
for numbers of packets bought from 1 to- How would other special offers (e.g.
‘Buy one, get one half price’) affect the
shape of this graph? If you were working
backwards from the graph, how could you
determine which offer is currently being
used?
Answers and comments are on pages 322–3.1 A novelty marketing company is selling
an unusual liquid clock. It consists of two
tubes as shown. The right-hand tube fills
up gradually so that it is full at the end
of each complete hour, and then empties
and starts again. The left-hand tube does
exactly the same in 12 hours. The time
shown on the clock is 9.15.Draw what the clock looks like at 4.20.End-of-chapter assignments