Sam is four years younger than Jo. But in five years' time Jo will be twice Sam's age now. How old are they now?
s = j-4
j+5 = 2s
Now go for it.
To solve this problem, let's break it down step by step:
1. Let's assign variables to represent their ages. We'll use "S" for Sam's age and "J" for Jo's age.
2. The problem states that Sam is four years younger than Jo, so we can write the equation: S = J - 4.
3. The problem also states that in five years' time, Jo will be twice Sam's age now. We can write the equation: J + 5 = 2(S).
4. Now, we have a system of two equations:
- Equation 1: S = J - 4
- Equation 2: J + 5 = 2S
5. We can solve this system of equations using substitution or elimination method. Let's use substitution:
- Substituting the value of S from Equation 1 into Equation 2, we have:
J + 5 = 2(J - 4)
6. Expanding the equation:
J + 5 = 2J - 8
7. Simplifying the equation:
J - 2J = -8 - 5
-J = -13
8. Multiplying both sides by -1 to solve for J:
J = 13
9. Substituting the value of J back into Equation 1 to find S:
S = 13 - 4
S = 9
So, Sam is 9 years old and Jo is 13 years old.