Concept tested : Grouping

Lowest common multiple of 4 and 3 is 12.
(4 × 3 = 12, 3 × 4 = 12)

Make the number of cans and bottles the same first.


Canned drink : 4 cans for $9

For 12 cans, cost will be $9 × 3 = $27

Bottled drink : 3 bottles for $5

For 12 bottles, cost will be $5 × 4 = $20


We let this be 1 group of cans and bottles.


Difference in price between the canned and bottled drinks in 1 group

= $27 - $20
= $7


Since the total difference is $42,

$42 ÷ $7 = 6

There are 6 such groups.

a)


Number of bottled drinks bought

= 12 per group × 6 groups
= 72

b)


In each group, the total cost of canned drinks is $27 (see earlier working)


For 6 groups,

Cost of canned drinks

= 6 x $27
= $162