# Sarin’s father crossing the Causeway part 10 (Math Question)

Standard

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 the kids can learn to deal with Math Modeling, Problem Sum from Lower Primary School to Upper Primary School level. This posting is a primary school math question on Fraction and Speed.

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 can read the posting on Sarin learns the concept of Fraction (mathematics concept) to understand the concept of Fraction.

Read also the posting on Sarin learns rate of change in school (Math Concept) to learn about concept of speed and relative speed.

Upper primary school mathematics question UPQ242

Sarin’s father started driving from Simei Town to JB Town at a constant speed at 1:00 p.m. After travelling for 4/7 of the journey, he passed by a lorry which was travelling at an average speed of 60 km/h in the opposite direction. When Sarin’s father reached JB town 2.5 h later, after meeting the lorry, the lorry was still 90 km away from Simei Town.
a) What was the distance between Simei Town and JB Town?
b) What time did Sarin’s father reach JB Town?

Solution:

After Sarin’s father met the lorry,

The distance that coverd by lorry in 2.5 h = 60 × 2.5 = 150km

The distance from Simei Town to the meeting point = 90 + 150 = 240km

When they meet, it is 4/7 of the journey for Sarin’s father

The fraction model,

From the above model

4 units = 240km

1 unit = 60km

The distance from Simei Town to JB Town = 7 × 60 = 420km

The speed of Sarin’s father = 3 × 60 ÷ 2.5 = 72km/h

The number of hours for Sarin’s father to travel from Simei Town to JB Town = 420 ÷ 72 = 5 15/18 h = 5 h 49.8 min

He start at 1 : 00pm, arrival Town B at 6 : 50pm