Maha Bodhi Sch 2007 PSLE Math Prelim Q47

Ali, Bala and Krishnan went to a shopping centre and bought a present for their friend. They agreed to share the cost of the present equally but Ali did not have any money with him that day and Bala did not bring enough to pay for his share. As a result, the amount of money Bala paid to that paid by Krishnan was 1 : 4. The next day, Bala returned $12 to Krishnan.

Find
a) how much money Bala brought along with him to the shopping centre.
b) the cost of the present.

Solution

Bala : Krishnan
1 : 4

1 + 4 = 5
5 units to be shared by 3 people -----
5 units divided by 3 = 1 and 2/3 units

Each person was expected to pay 1 and 2/3 units.

a)
Bala paid 1 unit the previous day, but paid $12 the next day, hence,

The balance 2/3 unit ----- $12
1/3 unit ----- $12 divided by 2 = $6
1 unit ----- $6 x 3 = $18

Answer: Bala brought along $18.

b)
Total cost ----- 5 units
5 units ----- $18 x 5 = $90

Answer: The cost of the present was $90.