Stay Sharp

1.)      5 × 4 - 3 + 3 × (4 - 3) × 2 + 7 =


2.)    


Two dice are rolled. What is the probability that two sixes appear?


3.)   The Morse code is a method to transmit letters and digits with dashes and dots, for example, to send a message by turning a flashlight on and off.

How many different code words can be made using three dots and three dashes in each word?


4.)   A special hair growth shampoo claims to cause hair to grow at a rate of 2 mm per day (i.e. in 24 hours) for at least 15 days. If my hair is 8 mm long before I use the shampoo on Monday morning, on the morning of what day will my hair be 2.8 cm long?


5.)   Identical letters stand for identical digits and different letters for different digits (i.e. 'ab' will be a 2 digit number). Determine the value of the letters such that all 3 horizontal and all 3 vertical calculations are correct. Which of the following statements is true?

c = 1
b = 6
c = 3
d = 2
d = 4
d = 8
a = 3