A box of biscuits
A box of biscuits contains 36 biscuits. 20 biscuits have foil wrappers. 15 are chocolate biscuits with foil wrappers. If 9 are not chocolate and do not have a foil wrapper, then how many chocolate biscuits are there?
The Secret of the Locked Chest
A chest is locked with a 5-digit code. The clues to the code are as follows: The first digit is a prime number. The second digit is twice the first. The third digit is the smallest odd number. The fourth digit is the difference between the third and first digit. The last digit is the sum of the first and fourth digit. What is the code to unlock the chest?
We can make a table for this one:
ReplyDelete| Foil wrappers | Not foil wrappers
_______________________|_________________ |____________________
Chocolate | 15 | 7
_______________________|_________________ |____________________
Not Chocolate | | 9
______________________ |_________________ |____________________
| 20 | 16
From this, we get a total of 15 + 7 = 22 chocolate biscuits