the average height of a class of 18 students is 105cm. After the arrival of 7 new students the average decreases by 5cm. Find sum of the heights of all the students in the class

1: 4 if the wew 35 surfboards at the beach how many were short boards?

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the plzzz write a proportion i will give you 100 points

The sum of the speeds of two trains is 720.2 mph. if the speed of the first train is 7.8 mph faster than the second train, find the speeds of each.