Friday, December 31, 2010

Decimal P6 2010 Pei Hwa CA1 Q18

7 apples cost $4.00.

9 oranges cost $11.00.
James bought a total of 1000 apples and oranges for $999.00.
How many apples and how many oranges did he buy?


7 A  +  9 O  --> 1000  Use 7 A and 9 O for the number of apples and oranges respectively to avoid handling fractions or decimals

4 A  +  11 O  -->  999

28 A  +  36 O  -->  4 x 1000 = 4000

28 A  +  77 O  -->  7 x 999 = 6993

41 O  -->  6993  -  4000  =  2993

9 O  -->  9/41  x  2993  =  657 oranges

7 A  -->  1000  -  657  =  343 apples


He bought 343 apples and 657 oranges.

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