Question 626316: Tom Johnson is 1 year less than twice as old as his sister. If the sum of their ages is 14 years, then Tom's age is: Answer by mengayzkie(3) (Show Source):
You can put this solution on YOUR website! Given:
x = Tom's age
y = sister's age
Tom Johnson is 1 year less than twice as old as his sister.
x = 2y - 1 ==> equation 1
The sum of their ages is 14
x + y = 14 ==> equation 2
Find:
Tom's age which is represented by x
Solution:
From equation 1; x = 2y - 1
Substitute the value of x from equation 1 to equation 2
x + y = 14
(2y - 1) + y = 14
3y - 1 = 14
3y = 14 + 1
3y = 15
divide both sides by 3 giving us:
y = 5
therefore the age of tom's sister is 5yrs old
To compute for Tom's age. Use any of the two equations given.
from equation 2:
x + y = 14
substitute y ( sister's age) to the equation
x + 5 = 14
x = 14 - 5
x = 9
Therefore Tom's age is 9 yrs old
Checking:
Use any of the equation 1 or 2 for checking.
Use equation 1:
x = 2y -1
substitute the value of x and y
9 = 2(5) - 1
9 = 10 - 1
9 = 9 ====>checked!
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