## For The Love of Calculators!Probability puzzles require you to weigh all the possibilities and pick the most likely outcome.Little Billy has a calculator with 15 buttons. He has 10 keys for 0-9, a key for addition, multiplication, division, and subtraction. Finally, he has an = sign. However, Mark the Meanie messed up the programming on Billy's calculator. Now, whenever Billy presses any of the number keys, it comes up with a random single-digit number. The same goes for the four operations keys (+,-,x, /). So whenever Billy tries to press the + button, the calculator chooses randomly between addition, multiplication, subtraction, and division. The only key left untouched was the = sign.
Now, if Billy were to press one number key, one operation key, then another number key, then the = button, what are the chances the answer comes out to 6? ## AnswerThere is a 4% chance.There are 16 possible ways to get 6. 0+6 1+5 2+4 3+3 6+0 5+1 4+2 9-3 8-2 7-1 6-0 1x6 2x3 6x1 3x2 6/1 There are 400 possible button combinations. When Billy presses any number key, there are 10 possibilities; when he presses any operation key, there are 4 possibilities. 10(1st#)x4(Operation)x10(2nd#)=400 16 working combinations/400 possible combinations= .04 or 4% Hide ## What Next?
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