Saturday, March 27, 2010

Fraction P6 2009 SA1 P2 Rosyth Q15

Mark had some stamps. He pasted 5/11 of the stamps on 5 postcards and 5 envelopes. On each postcard, he pasted 1/4 as many stamps as he pasted on each envelope. If he had 150 stamps left, how many stamps did he paste on each envelope? [4 marks]




He pasted 5/11 of the stamps on 5 postcards and 5 envelopes.
Find fraction of Stamps left. Then equate to the number.
1 - 5/11 --> 6/11
6 u --> 150

Find the number of stamps used.
5 u --> 1/6 x 150 = 125

On each postcard, he pasted 1/4 as many stamps as he pasted on each envelope.
Each postcard -- 1 u, each envelope -- 4 u. Find the total units in 1 set.
1 + 4 = 5

5 postcards and 5 envelopes
Find total units in 5 sets. Then equate to the total number of stamps used.
5 x 5 = 25
25 u --> 125

Find the number of stamps on each envelope.
4 u --> 4/25 x 125 = 20 stamps

He pasted 20 stamps on each envelope.

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