Answer :
Answer:
2,304 years old
Step-by-step explanation:
Given: Jennifer age = 18, Invested = $1000 at 8% interest
To find: How old would she be when the account is $128,000?
Wrong solution
Solution: To figure out how old she will be when her account is $128,000, simply find the difference between her current account value by her current age, by dividing. Then multiply the result by the future account value.
Step 1: [tex]\frac{1000}{18} = 55.5555555556[/tex]
Rounding, that is; 55.56
Step 2: Now, multiply the result by the future account value.
[tex]55.56[/tex] × [tex]128000 = 7111680[/tex]
Correct solution
Solution: To find out how old she will be when her account is $128,000, set up a fraction;
[tex]\frac{1000}{8} = \frac{12800}{x}[/tex]
Step 1: Divide the numbers
[tex]\frac{1000}{8} = \frac{128000}{x} \\\\\frac{500}{9} = \frac{128000}{x}[/tex]
Step 2: Multiply all terms by the same value to eliminate fraction denominators
[tex]\frac{500}{9} = \frac{128000}{x} \\\\x * \frac{500}{9} = x * \frac{128000}{x}[/tex]
Step 3: Cancel multiplied terms that are in the denominator
[tex]x *\frac{500}{9} = x * \frac{128000}{x} \\\\x * \frac{500}{9} = 128000[/tex]
Step 4: Re-order terms so constants are on the left
[tex]x * \frac{500}{9} = 128000\\\\\frac{500}{9} x= 128000[/tex]
Step 5: Combine multiplied terms into a single fraction
[tex]\frac{500}{9} x = 128000\\\\\frac{500x}{9} = 128000[/tex]
Step 6: Multiply all terms by the same value to eliminate fraction denominators
[tex]\frac{500x}{9} = 128000\\\\9 * \frac{500x}{9} = 9 * 128000[/tex]
Step 7: Cancel multiplied terms that are in the denominator
[tex]9 * \frac{500x}{9} = 9 * 128000\\500