Gasoline oil problem [Solved!]

X

I don't agree with your answer in exmple 4.

The gasoline-oil mixture is at 75% in 8L. 75% of 8 IS 6.Therefore 6L of gasoline cannot be what is required to make a 15:1 ratio of 8L of oil unless I didn't understand the question.

I think the answer should be 7.5L of gasoline to 0.5L of oil to make a 15:1 ratio of 8L of outboard engine mixture.

Relevant page

<a href="/basic-algebra/6-applied-verbal-problems.php">6. Applied Verbal Problems</a>

What I've done so far

I've read this many times but I don't get it.

X

Hello Hannah

You would be correct if we started with some (pure) oil and some (pure) gasoline.

But the question says that we started with (1) some pure gasoline and (2) some mix of oil/gasoline (that was 75% gasoline). It doesn't tell us how much of each, but we have to mix them to get the required 8 L of 15:1 mix.

The final answer means we have to add 6 L of gasoline and 2 L of the mix.

The amount of gasoline at the end will be

6 L (from the pure bit) plus 75% of 2L (1.5 L - from the mixed bit) = 7.5 L gasoline

and the amount of oil will be

25% of 2L (from the mixed part) = 0.5 L.

The final mix has the correct ratio. It took 6L of pure gasoline to get it.

Hope that makes sense

Regards

X

I got it now. Thanxx