# Sarin’s father crossing the Causeway part 9 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. The blog presenting Math Concept, Math Questions with solutions that teaches in Singapore Primary Schools. You or your kids can learn deal with Math Modeling, Problem Sum from Lower Primary School to Upper Primary School level. This posting is a primary school math question on Ratio and Problem Sum.

Read posting on Sarin’s father visits his friend in JB town to know about JB town as well as reading posting on Sarin’s father crossing the Causeway to know about the Johor-Singapore Causeway.

You should click and read posting on Sarin learns concept of ratio in school to understand mathematics concept of Ratio.

Upper primary school mathematics question UPQ169

At the Causeway, the number of motorcycles in Woodland Custom Checkpoint was 1/2 the number of cars. There were 220 more cars than motorcycles. After some motorcycles crossed the Woodland Custom Checkpoint, the number of cars in the Woodland Custom Checkpoint was ten times the number of remaining motorcycles. How many motorcycles crossed the Woodland Checkpoint?

Solution:

Draw a model based on the ratio on motorcycles and Cars at first

The number of motorcycles at first = 220

The number of cars at first = 2 × 220 = 440

Finally,

The motorcycles and cars = 1 : 10

10 units = 440

1 unit = 44

Motorcycles at the Woodland Custom Checkpoint = 44

Motorcycles crossed the Woodland Custom Checkpoint = 220 – 44 = 176

Alternative solution:

Start the model base on final ratio than work backward to ratio at first

From the model,

5 units = 220

1 unit = 44

Motorcycles crossed the Woodland Custom Checkpoint = 4 × 44 = 176