There are 90 students in the school band. 30% of them are sixth graders, 40% are seventh graders, and the rest are eighth graders. How many band members are 6th graders?

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Solve the given system of equations. 2y= -x+9 , 3x-6= -15

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?