Ai Tong School P6 SA1 2006 Math (Q42)

There were 128 cups on sale. ¾ of them were made of clay and the rest were made of plastic. When some clay cups were sold, the number of clay cups left was 3/7 of the total number of cups left.

(a) How many plastic cups were there?
(b) How many clay cups were sold?

Solution

(a) ¼ x 128 = 32
Answer: There were 32 plastic cups.


(b) Clay cups at first ----- 128 – 32 = 96

After selling



4 units ----- 32
1 unit ----- 32 divided by 4 = 8
3 units ----- 24

Therefore, number of clay cups sold is
96 – 24 = 72

Answer: 72 clay cups were sold.