Level 3
Carl had a total of 90 notes. The notes are $10 notes and $5 notes. After he spent 20% of the $10 notes and 60% of the $5 notes on a stereo system, he was left with 4 times as many $5 notes as $10 notes. How much did the stereo system cost?

Level 3
The ratio of the number of biscuits in Container H to the number of biscuits in Container J was 5 : 3. 20% of the biscuits in Container H and 0.6 of those in Container J were round. After transferring the biscuits between the 2 containers, the number of square biscuits in both containers are the same. Likewise, the number of round biscuits in both containers are the same. If a total of 162 of biscuits were moved, how many more biscuits were there in Container H than Container J at first?

Level 3
Mrs Yap had 40% more books than Mdm Zhang. Miss Lin had 20% fewer books than Mrs Yap. Mrs Yap and Mdm Zhang gave Miss Lin some books in the ratio of 1 : 4. As a result, Miss Lin had 50% more books than before. Given that Miss Lin had 423 more books than Mdm Zhang in the end, how many books did Mrs Yap give to Miss Lin?

Level 3
At an event held at the stadium, 80% of the audience were adults. The female audience was made up of 70% of the children and 30% of the adults. There were 64 more girls than boys.

1. How many people went to the stadium in total?
2. Some women left before the event ended, after which 20% of the remaining people at the stadium were women. How many women left the stadium before it ended?

Level 3
Oscar, Ethan and Fred had some balls. Ethan had 40% more balls than Oscar. Ethan had ³₅ of Fred's. After Oscar gave 18 balls to Ethan, he had ¹₂ of what Ethan had. How many more balls did Fred have than Ethan in the end?

Level 3
There were some avocados in 3 boxes, E, F and G. 30% of the number of avocados in Box E was equal to 60% of the number of avocados in Box F. The number of avocados in Box G was 60% of the total number of avocados in Box E and F. After Oscar removed 20% of the avocados in Box G, there were 88 more avocados in Box F than in Box G. In the end, how many avocados should be transferred from Box F to Box G so that the avocados in Box G would be the same as Box E?

Level 3
The average number of mangosteens in Carton C, Carton D and Carton E is 24 and it is 8 more than the average number of papayas in the 3 cartons. ¹₆ of the papayas are in Carton C and the papayas in Carton C is 80% of the number of papayas in Carton D. If each carton has the same number of fruits, what percentage of the fruits in Carton E are mangosteens?

Level 3
On Monday, 700 more youths than children attended a concert. On Tuesday, the number of youths decreased by 30% and the number of children increased by 80%. 1240 audience attended the concert on Tuesday. If each ticket cost $12, how much money was collected from the sale of concert tickets for the two days?

Level 3
Sarah bought a total of 300 big and small candies. Then she decided to exchange 60% of her big candies for the small ones in the ratio of 3 : 5. After the exchange, she had 366 candies. What percentage of the candies she bought were small ones?

Level 3
The number of 20-cent coins in a basket was 100% more than the number of 10-cent coins. 13 twenty-cent coins were taken out and exchanged for 10-cent coins. The number of 20-cent coins became ⁵₈ less than the number of 10-cent coins. How much money is there in the basket?