# A family in Singapore part 50 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings about Solving Singapore Primary School Mathematics. The blog presenting the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids will able to acquire knowledge of dealing with the Math Modeling, the Math Problem Solving and the Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Average Number.

You should read the posting on Sarin learns Average Number, Percentage and Charting in school (Math Concept) to understand the concept of Average Number.

Challenge yourself with the question before look for the given solution‼!

Upper primary school mathematics question UPQ436

Sarin’s father and his 6 friends have an average age of 54. If Sarin’s father is 48 years old, what is the average age of his 6 friends?

Solution:

The different between Sarin’s father and the total average age = 54 – 48 = 6 years

The average of the 6 friends = 54 + 6 ÷ 6 = 55 years

Alternative solution:

The total age of Sarin’s Father and the 6 friends = 7 × 54 = 378 years

The total age of the 6 friends = 378 – 48 = 330 years

The average age of the 6 friends = 330 ÷ 6 = 55 years