Question I got wrong: "Pete and his partner Mike made a huge profit in their..."

[HaveAQUESTION]

Question I got wrong: "Pete and his partner Mike made a huge profit in their..."

[FONT=&quot]Pete and his partner Mike made a huge profit in their software business together this year and have decided to use $20,000 of the profit for a Christmas donation to their favorite charities. Using the investment ratio each of them contributed to starting the business, Pete invested the most with 4:1 ratio to Mike. How much money will Mike get to donate to his charity?[/FONT]

I first tried dividing 20,000 by four and got 5,000, and got it wrong. The answer sheet told me I was supposed to multiply 20,000 by 1/5 and get 4,000 as my answer. My question is where in the problem am I supposed to get the idea to multiply 20,000 by 1/5?

 

[lev888]

Why did you divide by 4?

 

[mmm4444bot]

… where in the problem am I supposed to get the idea to multiply 20,000 by 1/5?

Multiplying by 1/5 is the same as dividing by 5.

You were on the right track, but maybe you didn't realize that the 4:1 ratio here compares four parts (Pete) to one part (Mike); there's five parts in total. The $20,000 needs to be divided into five parts. Pete donates four of them, and Mike donates one of them. :cool:​

 

[Dr.Peterson]

I first tried dividing 20,000 by four and got 5,000, and got it wrong. The answer sheet told me I was supposed to multiply 20,000 by 1/5 and get 4,000 as my answer. My question is where in the problem am I supposed to get the idea to multiply 20,000 by 1/5?

Dividing 20,000 by 4 would have been correct if $20,000 were Pete's amount. But it's the total, instead.

One way to visualize the problem is to see Pete's part as 4 equal blocks, and Mike's as another:

[FONT=courier new]+-----+-----+-----+-----+-----+
|         Pete          |Mike |
+-----+-----+-----+-----+-----+[/FONT]

Then the $20,000 corresponds to all 5 blocks, not just 4. Each block is 1/5 of the total.