How many ways are there to distribute five balls into seven boxes if each box must have at most one ball in it if a) both the balls and boxes are labeled? b) the balls are labeled, but the boxes are unlabeled? c) the balls are unlabeled, but the boxes are labeled? d) both the balls and boxes are unlabeled?

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

what grade level is this? need to know so i can look in my old textbooks!