SOLUTION: Jenny is twice as old as Jimmy. Jesse is 10 years older then jimmy. If the sum of their ages is 90, how old is Jenny?

Question 774394: Jenny is twice as old as Jimmy. Jesse is 10 years older then jimmy. If the sum of their ages is 90, how old is Jenny?
Found 2 solutions by lwsshak3, DrBeeee:
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
Jenny is twice as old as Jimmy. Jesse is 10 years older then jimmy. If the sum of their ages is 90, how old is Jenny?
***
let x=Jimmy's present age
2x=Jenny's present age
x+10=Jesse's present age
x+2x+x+10=90
4x=80
x=20
2x=40
how old is Jenny? 40
Answer by DrBeeee(684) (Show Source): You can put this solution on YOUR website!
To avoid all the J's,
Let a = Jenny's age
Let b = Jimmy's age
Let c = Jesse's age
REM: when you have 3 unknowns, you need 3 equations!
The problem statement provides us with the following three equations.
(1) a = 2*b,
(2) c = 10 + b, and
(3) a + b + c = 90
Put (1) and (2) into (3) to get
(4) 2*b + b + 10 +b = 90 or
(5) 4*b = 90 - 10 or
(6) 4*b = 80 or
(7) b = 20
From (1) we get
(8) a = 2*20 or
(9) a = 40
And from (2) we get
(10) c 10 + 20 or
(11) c = 30
Let's check our ages with (3).
Is (40 + 20 + 30 = 90)?
Is (90 = 90)? Yes
Answer: Jenny is 40 years of age.
RELATED QUESTIONS
Sara is twice as old as Jimmy. Three years ago, the sum of their ages was 39. How old is... (answered by math_helper)
jimmy is 3 years older than jeff.andy is 1/4 of jimmy age.john is twice as old as... (answered by RedemptiveMath)
Jimmy is 6 years older than Tom. In three years time Jimmy will be twice as old as Tom.... (answered by math_helper)
Jimmy is 3 years older than his brother Bill. The sum of 3 times Jimmy's age and twice... (answered by Stitch)
Jenny and Ann are sisters. Jenny is three times older than Ann. In four years, Jenny will (answered by ewatrrr)
Amanda is 20 years older than Jenny. the sum of their ages is 44. How old are... (answered by JulietG)
Marcia is 53 years older than her grandson Jimmy. The sum of their age is 75. How old are (answered by josgarithmetic)
8 years ago, Jimmy was three times as old as Anne. In 4 years, Jimmy will be 3/2 of... (answered by ankor@dixie-net.com)
paolo is 5 years older than jenny. eight years ago paolo was twice as old as jenny .how... (answered by JulietG)