Fred is five times as old as Grace. In eight years time, Fred will be three times as old as Grace. What are their ages?

Step-by-step explanation: in the question it is given that, Fred is five times as old as Grace, it means that the present age of Fred is 5 times the age of Grace. in the solution we have assumed Grace age to be X years. if Grace age is X years then the age of Fred is five times that of Greece age that is 5x years. now it is given in the question that in 8 years of time Fred's age will be three times as old as Grace. as it is given in the question as 8 years then it means that we have to add 8 years to both the present age of grace as well as Fred's age. now if we'll add 8 years in both grace age and frads age then it will be X + 8 years and 5 x + 8 years respectively. now it is said that in 8 years of time Fred's age will be three times of grace age. now to make it equal we have to put that three times in Grace age, so that three times of grace age will be equal to Fred's age. then you simply need to solve the equation As given in the solution then we will get X equal to 8. we have got Grace present age to be 8 years and Fred's present age to be 40 years uh i hope this hepls you do your work :D

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240