13. (a) A man bought two books for Rs 1040. He sold one at a loss of 15% and other at a profit of 36% then he found that each book was sold for the same price. Find the cost price of each book.​

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14