Why is it important to represent these unknown values with variables

Thief steals an atm card and must randomly guess the correct threethree?-digit pin code from a 99?-key keypad. repetition of digits is allowed. what is the probability of a correct guess on the first? try?

What is the value of 5^4/5^6

What is the value of x in the equation 7x + 2 y = 48, when y = 3? COF x = 6 x = 7 x = 8 x = 9

Each side of the square below is 20 centimeters. The area of the circle inside the square is about 314 square centimeters. a. 43/200 b. 43/157 c. 157/200 d. 200/157

Which is the prime factorization of 114

Find the unit rate 322 miles on 14 gallons of gas

Factor the expression x^{2} + 4x-21

Consider two boxes, one containing one black and one white marble, the other, two black and one white marble. a box is selected at random and a marble is drawn at random from the selected box. what is the probability that the marble is black? 37.

If runners in a long distance race were to run straight from the starting line to the finish line they would run 13 kilometers. However, the road they run makes them travel longer than that.

If a train leaves the station at 7:00 AM and travels at 56 mph, at what time would it arrive at the next town that is 450 miles away?