Answer:

Step-by-step explanation:
Given Data,
Q=23000 J
c=4.184 J/g °c
Δt= 68 °c
m=?
By using this equation,
Q=mcΔt

If I put this into an equation it would look like 2x+2= 66. 66-2= 64. You do this because to get x you have to reverse the equation, but you have to do the number not connected to x first. Then 2x= 64. So you divide 64 by 2 which is 32. So Jordan is 32 years old. Hope this helped!
You can solve the problem this way:
Your money is increading $6 a week while sister's is decreasing $7 a week (because she isn't saving any and is spending $7 of what she has weekly)
Your money each additional week vs sister''s:
80/145 (Week 0)
86/138 (Week 1)
92/131 (Week 2)
98/124 (Week 3)
104/117 (Week 4)
110/110 (Week 5) The amounts are the same in 5 weeks.