A security company can use number 1 -7 to create a 5 digit lock combo. No numbers can be repeated and the first and last digit must be odd. How many unique lock combos can be created?  Choose the correct option:
A) 60
B) 120
C) 180
D) 240
E) 300
Lets take it this way, first and last digit needs to be odd so that means it take 1,3,5,7   So, for first digit we have 4 options and for last digit we have 3 digits   for the rest of the 3 digits we have 5 digits to choose from so 5C3=105C3=10 options   Total combinations = 4 * 3 * 10= 
<gadget id="calculator">4 * 3 * 10</gadget>
<output>120</output>
120   ANS:120
<result>B</result>
A security company can use number 1 -7 to create a 5 digit lock combo. No numbers can be repeated and the first and last digit must be odd. How many unique lock combos can be created?