322 Answers to assignments
2 In 5 minutes Finn has travelled 0.5 km.
Finn travels at 6 km/h, Alice at 18 km/hr.
Alice is catching up with him at 12 km/hr so
it takes her^0512. hours to catch up. In this time
she has travelled 18 ×^0512. km, or 0.75 km, so
she overtakes him at the halfway point.
The journey takes 15 minutes for Finn
and 60 ×^1518. = 5 minutes for Alice, so for
them to arrive together, she would have
to leave 10 minutes after him.(^3) Number
bought
Price Unit price
1 $1.20 $1.20
2 $2.40 $1.20
3 $2.40 $0.80
4 $3.60 $0.90
5 $4.80 $0.96
6 $4.80 $0.80
7 $6.00 $0.86
8 $7.20 $0.90
9 $7.20 $0.80
10 $8.40 $0.84
1 2345678910
0.70
0.80
0.90
1.00
1.10
1.20
1.30
Number bought
Unit
pr
ice ($)
One or two alternative offers should be
selected (for example the ‘buy one, get one
half price’ suggested) and the tabulation and
graphing procedure shown above should be
repeated for these.
1¢ 2¢ 5¢ Total
1 2 9 50¢
1 3 8 47¢
1 4 7 44¢
1 5 6 41¢
2 3 7 43¢
2 4 6 40¢
3 4 5 36¢
We need to look at each of A–D in turn.
A is not sufficient information as two
options have three 2¢ coins.
B is not sufficient as two totals are
multiples of 10¢.
C identifies a unique combination: in the
second to last row, 5¢ coins add to 30¢
which is^34 of the total, so this is the
correct answer.
D is not sufficient because two options
(rows 3 and 5) have two more 5¢ coins
than 1¢ and 2¢ together.
3.11 Choosing and using models
1 Both tubes should be approximately^13 full
as 4 hours is^13 of 12 hours and 20 minutes
is^13 of 60 minutes. Strictly speaking, the
hours tube should be a very small amount
fuller as it should show 4 13 hours.