SAT Math: 5:2 Peanut-Cashew Mixture Question

[I'm]

Homework Statement

In a Mixture of peanuts and cashews, the ratio by weight of peanuts to cashews is 5 to 2. how many pounds of cashews will there be in 4 pounds of this mixture?

Homework Equations

The Attempt at a Solution

I used 5/2 as seven pounds in the original ratio.

Then I tested out some numbers for 2, such as 1.2, 1.4 and they all added up to a number close to four. I didn't reaaly know how to set the problem up so I ended up getting it wrong. I got 1.2.

 

[Doc Al]

I used 5/2 as seven pounds in the original ratio.

Nothing wrong with thinking that 5 lbs of peanuts plus 2 lbs of cashews = 7 lbs.

To reduce 7 lbs to 4 lbs, what would you multiply by? Multiply all quantities by the same number to retain the 5/2 ratio.

 

[I'm]

I just got it out of insight from your reply. Thank you.