The cost of a kiwi fruit was ¼ that of a rock melon. Melvin spent 4/7 of his money on 12 rock melons and 4 kiwi fruits. Then he used the remaining amount of money to buy 3 more rock melons and some kiwi fruits. How many kiwi fruits did he buy in all?
Solution
Kiwi fruit ----- 1 unit
Rock melon ----- 4 units
12 rock melons + 4 kiwi fruits ----- 4/7 of money
(12 x 4 units) + (4 units) ----- 4/7 of money
48 units + 4 units ----- 4/7 of money
52 units ----- 4/7 of money
4/7 of money ----- 52 units
1/7 of money ----- 52 units divided by 4 = 13 units
The remaining amount of money he had was 3/7, therefore
3/7 of money ----- 13 units x 3 = 39 units
He used this amount of money to buy 3 rock melons and some kiwi fruits.
3 rock melons + unknown no. of kiwi fruits ----- 39 units
(3 x 4 units) + ? ----- 39 units
12 units + ? ----- 39 units
? ----- 39 units – 13 units = 27 units
1 unit ----- 1 kiwi fruit
27 units ----- 27 kiwi fruits
Total no. of kiwi fruits bought -----
4/7 of money was spent on 12 rock lemons and 4 kiwi fruits.
3/7 of money was spent on 3 rock lemons and 27 kiwi fruits.
Total no. of kiwi fruits ----- 4 + 27 = 31
Answer: He bought a total of 31 kiwi fruits.
Thursday, April 17, 2008
Ai Tong School P5 SA1 2006 Math (Q43)
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Nanyang Primary School
SA2 2006 Primary 5
Question 46:
Three girls shared a sum of money. Cathy received $180 more than Betty. The total amount Betty and Cathy received was 3 times the amount Alice received. The amount Alice and Cathy received was 5 times the amount Betty received. What was the sum of money shared by the three girls?
pls enlighten. thanks
thanks a lot.
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