# Sarin’s family and Ramadan Part 5 (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, 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 an upper primary school math question on Fraction, Ratio, Percentage and Problem Sum.

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

To read also the postings on Sarin learns the concept of Fraction (mathematics concept) and Sarin learns concept of ratio in school to understand the concept of Fraction and Ratio.

Try to solve the question before look out for the solution‼

Upper primary school mathematics question UPQ243

Sarin, Hairu and Fatimah decided to buy a present for their friend. Sarin agreed to contribute 3/10 of the cost of the present while Hairu agreed to pay 60% of the remaining amount. The balance will be paid by Fatimah. When they purchased the present, the price of the item had increased to 20%. As a result, Sarin paid \$27.90 for his share.
a) What was the original price of the present?
b) How much did Fatimah have to pay in the end?

Solution:

Hairu is paying 60% of the remaining amount

Based on the fraction model,

Hairu is paying 7 × 0.6/10 = 4.2/10 fraction of the total amount

Fatimah is paying 7/10 – 4.2/10 = 2.8/10 fraction of the total amount

The faction model, The ratio of the amount they need to pay,

Sarin : Hairu : Fatimah = 30 : 42 : 28 = 15 : 21 : 14

The actual amount paid by Sarin was \$27.90 after 20% increased in price The amount he should paid before increase = 27.90 ÷ 1.2 = \$23.25

Based on the payment ratio,

15 units = 23.25

1 unit = 1.55

The original price of the gift = 50 × 1.55 = \$77.50

The amount Fatimah need to pay = 1.2 × 14 × 1.55 = \$26.04