Se compran libros a razón de 3 libros por 35 soles, y se venden libros a razón de 21 libros por 200 soles ¿Cuántos libros se vendieron, si la ganancia fue 685 soles?

Use the normal approximation to the binomial distribution to answer this question. fifteen percent of all students at a large university are absent on mondays. if a random sample of 12 names is called on a monday, what is the probability that four students are absent?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?

The areas of two similar triangles are 72dm2 and 50dm2. the sum of their perimeters is 226dm. what is the perimeter of each of these triangles?