If x = kc and y = kt, then y - x = ?

What is the number of different committees of 4 people that can be selected from a group of 10 people?

An investor purchased 20 shares of a certain stock at a price of $45.75 per share. Later this investor purchased 30 more shares at a price of $46.25 per share. What was the average (arithmetic mean) price per share that this investor paid for the 50 shares?

If n denotes a number to the left of 0 on the number line such that the square of n is less than ~$\frac{1}{100}$~, then the reciprocal of n must be?

A fast-food company plans to build 4 new restaurants. If there are 12 sites that satisfy the company's criteria for location of new restaurants, in how many different ways can the company select the 4 sites needed for the new restaurants if the order of selection does not matter?

A company wants to buy computers and printers for a new branch office, and the number of computers can be at most 3 times the number of printers. Computers cost $1,500 each, and printers cost $300 each. What is the greatest number of computers that the company can buy if it has a total of $9,100 to spend on computers and printers?

If Sally drives at a constant speed of 50 miles per hour, how many minutes will be required for her to drive 10 miles?

Which of the following lists the number of points at which a circle can intersect a triangle?

A pair of shoes is on sale for $60. If this price is 20 percent less than the regular price of the shoes, what is the regular price of the shoes?

A certain telephone company offers two plans, A and B. Under plan A, the company charges a total of $0.60 for the first 7 minutes of each call and $0.06 per minute thereafter. Under plan B, the company charges $0.08 per minute of each call. What is the duration of a call, in minutes, for which the company charges the same amount under plan A and under plan B ?