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You can click here and read the posting A family in Singapore about Sarin’s family.
Read also the posting on Sarin learns the concept of Ratio in School (mathematics concept) to understand the concept of Ratio.
Challenge yourself with the question before look for the given solution‼!
Upper primary school mathematics question UPQ563
Sarin, Hairu and Fatimah took their parents out for a dinner. If Sarin paid for the dinner, the amount of money that Sarin, Hairu and Fatimah left will be in the ratio 3 : 8 : 9 respectively. If Fatimah paid for the dinner, the amount of money Sarin, Hairu and Fatimah left would be in the ratio 5 : 4 : 1 respectively. If Hairu paid for the dinner, the amount of money Sarin, Hairu and Fatimah left would be in the ratio 10 : 1 : 9 respectively. Sarin had $40 more than Hairu. How much did the dinner cost?
Disregarding of who paid for the dinner, the left over amount is the same.
If Sarin Paid,
Sarin : Hairu : Fatimah : Total = 3 : 8 : 9 : 20
If Fatimah Paid,
Sarin : Hairu : Fatimah : Total = 5 : 4 : 1 : 10 = 10 : 8 : 2 : 20
If Hairu Paid,
Sarin : Hairu : Fatimah : Total = 10 : 1 : 9 : 20
When Fatimah paid, Sarin and Hairu need not to pay for the dinner,
The ratio of their money is the original amount
Sarin has $40 more than Hairu
The difference = $40 = 2 units
1 units = $20
When Sarin paid,
The amount he paid in units = 10 – 3 = 7 units
The dinner cost = 7 × 20 = $140