# Sarin’s family took a train part 1 (Math Question)

Standard

The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics. You or your kids can learn dealing with Math modeling, Problem Sum from Lower Primary School to Upper Primary School level in Singapore school. This posting is a primary school math question on Speed and Rate of Change.

Read the posting on Sarin’s family took a train about Sarin’s family had their train ride from Singapore Tanjong Pagar Train Station.

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 UPQ175

A train KTM15 left Singapore Tanjong Pagar Station for Malaysia Kluang Station. At the same time, a return train KTM81 left Kluang Station for Tanjong Pagar Station. The average speed of the train KTM15 was 90 km/h while the speed of the train KTM81 was 70 km/h. The two trains passed each other at a point 36 km away from the mid-point between Tanjong Pagar Station and Kluang Station. What was the distance between Tanjong Pagar Station and Kluang Station?

Solution:

The speed of train KTM15 faster than train KTM81 = 90 – 70 = 20 km/h

Time need to travel to mid-point = 36 ÷ 20 = 1.8 h

The relative speed of the train = 90 + 70 = 160 km/h

Distance between Town A and Town B = 160 × 1.8 × 2 = 576km