You can read posting **Sarin and his coin bank** on the story of coin bank.

Read also posting on **Sarin and the million numbers** to understand concept of dollars and cents.

Lower primary school mathematics question LPQ48

Sarin had a total of twenty $10-notes and $5-notes in his coin bank. The total value of all the notes was $120. How many $10-notes did he have?

Solution:

A set of 1 $10-note and 1 $5-note give value of = 10 + 5 = $15

If there are 10 sets, the value = 10 × 15 = $150

It is more than $120 by $30

To reduce $10-notes and increase $5

We needs to reduce 30 ÷ 5 = 6 $10-notes to get to $120

The number of $10-notes = 10 – 6 = 4

The number of $5-notes = 10 + 6 = 16

Alternative solution:

Use guess and check method

Start the guess from 10 $10-notes and 10 $5-notes

Remember the total number of notes = 20 (1^{st} check)

Then base on total value coputed to decide increase or reduce the number of notes

Sarin has 4 ten dollar notes in his coin bank.

**More problem sum questions click here**

**More guess and check questions click here**

### Like this:

Like Loading...

*Related*