Level 3
Jerry bought 4 packets of biscuits. Katrine bought 2 times as many packets of biscuits as Jerry. If each packet costs $8, how much did Katrine spend on the biscuits?
Level 3
There are 624 stamps in a bag. Given that there are four times as many yellow stamps as red stamps and twice as many white stamps as yellow stamps, how many stamps in the bag are yellow?