You can read posting **Sarin and his coin bank** on the story of coin bank. Read also postings on **Sarin and the million numbers** to understand concept of dollars and cents and **Sarin learns the concept of Fraction (mathematics concept)** on concept of fraction.

Upper primary school mathematics question UPQ25

Sarin has 279 coins in his coin bank. 3/5 of them are 20-cent coins and the rest are 50-cent coins. He spent 1/3 of the 50-cent coins on a book. How much did the book cost?

Solution:

Cost of a book = 279 × 2/5 × 1/3 × 50

= 1860cents = $18.60

Alternative Solution:

The fraction model

1/3 of the 50-cent coins used on a book

The 20-cent coins is 3/5 of the fraction of the total coins

The 20-cent coins take 3 parts and 50-cent coins take 2 parts

We can divide the 2 parts to 6 sub-parts and 2 sub-parts as the cost of the book

From the model

The total number of coins = 279

15 units = 279

1 unit = 18.6

The cost of a book = 2 × 18.6 ×0.50 = $18.60

### Like this:

Like Loading...

*Related*