Level 3
Zoe had some yellow stickers and pink stickers in 2 baskets. In Basket A, the ratio of the number of yellow stickers to pink stickers was 6 : 5. In Basket B, the number of yellow stickers was 2 times the number of pink stickers. Zoe transferred ²₅ of the pink stickers from Basket A to Basket B. The number of stickers in Basket A became 144 and the ratio of the number of yellow stickers to pink stickers in Basket B became 6 : 7.

1. How many pink stickers were transferred from Basket A to Basket B?
2. What was the number of stickers in Basket B after the transfer?

Level 3
Xuan, Penny, Kate and Violet went to buy a gift for their grandmother. They shared the cost equally among themselves. However, Violet forgot to bring her money. So, the other 3 girls paid for the gift first. Kate paid ³₅ of the amount Xuan and Penny paid. Penny paid $11 more than Xuan. The next day, Violet returned $76 to Kate and some money to Xuan and Penny. How much did Violet return to

1. Xuan?
2. Penny?

Level 3
Oscar Mobile Company has a few mobile phone service plans. Plan A offers 270 SMS and 90 minutes of talk time for $25.20. Plan B offers 370 SMS and 190 minutes of talk time for $35.20. Oscar Mobile Company is also going to launch Plan C which offers 170 SMS and 260 minutes of talk time. How much should Oscar Mobile Company charge for Plan C if the cost per SMS and the cost per minute of talk time do not vary across the three plans?

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?

Level 3
20% of the people are performers for a concert and the rest are spectators. 80% of the spectators are adults and there are 3900 more adults spectators than children spectators. How many adult spectators must leave so that 25% of the people in the concert are adult spectators?