Question
POLYA'S FOUR_STEP PRODLEM-SOLVING STRATEGY John is three times as old as his son. In 12 years, he will be twice as old as his son. How old are John and his son now?
Solution
4.3
(321 Votes)
Caius
Elite ยท Tutor for 8 years
Answer
1. S = 24 2. J = 72
Explanation
This problem can be solved by setting up two equations and then solving for the two variables. Let's denote:- J as John's current age- S as his son's current ageIt states in the word question that "John is three times as old as his son", following into equation one: J = 3SIt also mentions that "In 12 years, John will be twice as old as his son". By adding 12 years to both of their ages, and setting up the equation as such: J + 12 = 2 * (S + 12)Now with these two derived equations: 1. J = 3S2. J + 12 = 2S + 24, using the substitution method, we can substitute J from the first equation (J=3S) into the second equation into the "J" of second equation and simplify to get the value of S. Once value of S is found, it can be put into the equation J=3S to find J's value. Then we have the age of both John and his son.