Jewel is 7 years old and John is 16 years younger than Dave. One year ago, Dvae's age was twice the sum of Jewel's and John's ages. Fine the current age of each of them.

Jewel is 7 years old

John is 1 year old

Dave is 17 years old

Step-by-step explanation:

From the question we are told that:

Jewel age is

John age

Dave's age a Year ago

So that Dave.s age this Year could be

Simplifying Equation for Dave's age we have

Dave is 17 years old

Therefore

Johns age is

John is 1 year old

(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