E ECBERNA New member Joined Oct 10, 2011 Messages 1 Oct 10, 2011 #1 Can anyone help me with this problem. In 3 years David will be twice as old as he was last year, How old is David now?
Can anyone help me with this problem. In 3 years David will be twice as old as he was last year, How old is David now?
B blink New member Joined Oct 10, 2011 Messages 10 Oct 10, 2011 #2 x+3=2(x-1) x+3=2x-2 x+5=2x x+5-x =2x-x 5=x So 5+3=8 5-1=4 He is 5
S soroban Elite Member Joined Jan 28, 2005 Messages 5,584 Oct 10, 2011 #3 Hello, ECBERNA! In 3 years David will be twice as old as he was last year. How old is David now? Click to expand... Set up some relations. Let x\displaystyle xx = David's age now. In 3 years, he will be 3 years older: .x+3\displaystyle x+3x+3 And last year, he was one year younger: .x−1\displaystyle x-1x−1 Now translate the English into Algebra: . . In 3 years⏟x+3 will be⏟= twice⏟2 × last year⏟(x−1)\displaystyle \underbrace{\text{In 3 years}}_{x+3} \:\underbrace{\text{will be}}_{=}\: \underbrace{\text{twice}}_{2\:\times}\: \underbrace{\text{last year}}_{(x-1)}x+3In 3 years=will be2×twice(x−1)last year There is our equation! .. . x+3 = 2(x−1)\displaystyle x + 3 \:=\:2(x-1)x+3=2(x−1) Got it?
Hello, ECBERNA! In 3 years David will be twice as old as he was last year. How old is David now? Click to expand... Set up some relations. Let x\displaystyle xx = David's age now. In 3 years, he will be 3 years older: .x+3\displaystyle x+3x+3 And last year, he was one year younger: .x−1\displaystyle x-1x−1 Now translate the English into Algebra: . . In 3 years⏟x+3 will be⏟= twice⏟2 × last year⏟(x−1)\displaystyle \underbrace{\text{In 3 years}}_{x+3} \:\underbrace{\text{will be}}_{=}\: \underbrace{\text{twice}}_{2\:\times}\: \underbrace{\text{last year}}_{(x-1)}x+3In 3 years=will be2×twice(x−1)last year There is our equation! .. . x+3 = 2(x−1)\displaystyle x + 3 \:=\:2(x-1)x+3=2(x−1) Got it?
