Regina’s teacher recently gave her a homework assignment on solving equations. Since she has been thinking about saving for a ne
w cell phone, she decided to use the assignment as an opportunity to model a savings plan.
She created this equation to model the situation. In it, y represents the total amount saved for the new cell phone, 74 is the amount of money she has now, 40 is the amount of money she saves each month for the phone, and x represents the number of months since she started saving a regular amount:
74 + 40x = y.
She then solved the equation to determine how many months she’d need to save to have enough to purchase the new cell phone. Review her work, and select the error.
She created this equation to model the situation. In it, y represents the total amount saved for the new cell phone, 74 is the amount of money she has now, 40 is the amount of money she saves each month for the phone, and x represents the number of months since she started saving a regular amount:
74 + 40x = y.
She then solved the equation to determine how many months she’d need to save to have enough to purchase the new cell phone. Review her work, and select the error.
2 answers:
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ANSWER
Find out the how much fluid should be drained and replaced with pure antifreeze so that the new mixture is 60% antifreeze .
To proof
let us assume that the fluid should be drained and replaced with pure antifreeze be x .
As given
A radiator contains 10 quarts of fluid, 30% of which is antifreeze.
Now write 30% in the decimal form
Now write 60% in the decimal form
After drained and replaced the fluid with pure antifreeze than the quantity becomes = ( 10 - x )
The quantity of antifreeze is
The fluid should be drained and replaced with pure antifreeze so that the new mixture is 60% antifreeze .
than the equation becomes
solyving
100x +300 - 30x = 600
70x = 300
x = 4.28 quarts (approx)
Hence 4.28 quarts (approx) fluid should be drained and replaced with pure antifreeze so that the new mixture is 60% antifreeze .
Therefore the option (c.) is correct .