[Guest]

Steve owns an antique car, which is on its second engine. The combined age of the car and the engine is 84 years. The car is currently twice as old as the engine was when the car was as old as the engine is now. How old are they now?

[Guest]

How's this?

let c = the cars current age

let e = the engines current age

c + e = 84

c = 2(e - (c-e))

c = 2e - (2c - 2e)

add 2c to both sides for

3c = 4e

multiply first equation by 3 for

3c + 3e = 252

Since 3c = 4e, substitute it in for

4e +3e =252 7e = 252

e = 36

c = 84 - 36

c = 48

[dark_magician_92]

Steve owns an antique car, which is on its second engine. The combined age of the car and the engine is 84 years. The car is currently twice as old as the engine was when the car was as old as the engine is now. How old are they now?

very cool puzzle

let car be x yrs old and engine be y,

hence x-y years ago, car's age= y, engine's age=2y-x,

hence x=2(2y-x) and x+y=84,

we get x=48 and y=36

[Guest]

Steve owns an antique car, which is on its second engine. The combined age of the car and the engine is 84 years. The car is currently twice as old as the engine was when the car was as old as the engine is now. How old are they now?

car-x

engine-84-x

few years ago

car-84-x

engine-x/2

x-(84-x) = (84-x)-x/2

x-84+x = [2(84-x)-x]/2

2x-84 = [168-2x-x]/2

2(2x-84) = 168-3x

4x-168 = 168 - 3x

4x+3x = 168+168

7x = 336

x = 336/7

x = 48

car=48years

engine=84-48=36years

Edited January 16, 2011 by New member

[Guest]

car = 56, engine = 28 - car is twice as old as engine & 28+56 = 84