On a busy day, a shop sells a total of 15 desks and chairs for a total amount of $960.The desks sell for $120 each and the chairs sell for $50 each. (a) Express the information as two equations. Let d equal the number of desks and let c equal the number of chairs.
(b) Solve the equations simultaneously to find how many of each were sold.

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

What are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.