Can you solve this 7th grade math problem?

[disneyeveryyear]

This problem was included in my 7th grade son's homework last night. Both DH and I are college graduates with math backgrounds (not degrees in math). Neither of us could figure it out. I felt incredibly stupid to not be able to do 7th grade math.

A vote was held on a controversial subject. 40% of Democrats and 92.5% of Republicans voted for the bill. If 68% of all those present voted for the bill, what is the ratio of Democrats to Republicans?

If you figure this out, could you let me know the answer and how you worked it out?

 

[singingpixie]

Here goes:

.40D + .925R = .68 (D+R) (original scenario)
.40D + .925R= .68D + .68R (distribution)
.245R=.28D (subtract to get like variables on each side)
245 Republicans to 280 Democrats (multiplied to get whole numbers)

Anyone want to check my work?


ETA I think I did it wrong... I think what I got (before the last line) implies that 24.5% of republicans are the same number of people as 28% of democrats... and in that case I'm stuck. I'll keep thinking. Maybe the answer is that there is 1 Republican for every 1.1428 Democrats?

 

[tink1978]

This problem was included in my 7th grade son's homework last night. Both DH and I are college graduates with math backgrounds (not degrees in math). Neither of us could figure it out. I felt incredibly stupid to not be able to do 7th grade math.

A vote was held on a controversial subject. 40% of Democrats and 92.5% of Republicans voted for the bill. If 68% of all those present voted for the bill, what is the ratio of Democrats to Republicans?

If you figure this out, could you let me know the answer and how you worked it out?

I have no idea....I have a hard time understanding the new ways of doing 2nd grade math...good luck!!

 

[Cindy's Mom]

This problem was included in my 7th grade son's homework last night. Both DH and I are college graduates with math backgrounds (not degrees in math). Neither of us could figure it out. I felt incredibly stupid to not be able to do 7th grade math.

A vote was held on a controversial subject. 40% of Democrats and 92.5% of Republicans voted for the bill. If 68% of all those present voted for the bill, what is the ratio of Democrats to Republicans?

If you figure this out, could you let me know the answer and how you worked it out?

thanks disneyeveryyear, just reading that gave me a headache, I'm not even going to try to solve it.

 

[dwbakerjr]

0.4 D + 0.925 R = 0.68 (R + D)
0.4 D + 0.925 R = 0.68 R + 0.68 D
0.4 D + 0.925 R - 0.68 R = 0.68 D
0.4 D + 0.245 R = 0. 68 D
______ 0.245 R = 0.68 D - 0.4 D
______ 0.245 R = 0.28 D
______ 0.8571 R = D

i.e. There are (approximately) 85 to 86 percent as many Dems and Repubs.

If 100 senators voted, there would be 54 Repubs, 46 Dems;
if 436 reps voted, there would be 235 Repubs, 201 Dems.

 

[Lisa loves Pooh]

Well I suck at ratios....

This is what I got--but it isn't a ratio.

Let D be the # of all Dem's voting
Let R be the # of all Rep's voting

Assuming voters are one party or the other, let Z be the total number of voters.

Z = D + R

.68Z = total number of votes
.4D + .925R = total numberof votes

.68Z = .4 D + .925 R

.68 (D + R) = .4 D + .925 R

.68D + .68 R = .4 D + .925 R

.28 D = .245 R

.28/.245 = R/D

.875 = R/D

7R to 8D (had to do my usual math cheat on this part--dividing fractions until I go the one that corresponded with the above decimal)



That is as far as I got and I am probably wrong.

Then someone will post the real answer and it will be clear to me!!!!

ETA: Wow--I got the same answer as everyone else.

 

[Trish Bessette]

Wow, I don't know the answer either. However, I just had to let you know that my oldest DD is in 7th grade and she just made Honor Roll for the first semester I am so proud of her because Math was a constant struggle for her. I can't even begin to tell you how much extra effort she put into math. WOrst part is I can't even begin to help her!

 

[javaj]

Here goes:

.40D + .925R = .68 (D+R) (original scenario)
.40D + .925R= .68D + .68R (distribution)
.245R=.28D (subtract to get like variables on each side)
245 Republicans to 280 Democrats (multiplied to get whole numbers)

Anyone want to check my work?


ETA I think I did it wrong... I think what I got (before the last line) implies that 24.5% of republicans are the same number of people as 28% of democrats... and in that case I'm stuck. I'll keep thinking.

Almost correct, until the last line.

.245R = .28D

.245/.28 = D/R

245/280 = D/R -- multiply both sides by 35/35

7/8 = D/R -- for every 7 democrats, there are 8 Republicans

 

[mickeyfan2]

Well I suck at ratios....

This is what I got--but it isn't a ratio.

Let D be the # of all Dem's voting
Let R be the # of all Rep's voting

Assuming voters are one party or the other, let Z be the total number of voters.

Z = D + R

.68Z = total number of votes
.4D + .925R = total numberof votes

.68Z = .4 D + .925 R

.68 (D + R) = .4 D + .925 R

.68D + .68 R = .4 D + .925 R

.28 D = .245 R

.28/.245 = R/D

.875 = R/D

7R to 8D (had to do my usual math cheat on this part--dividing fractions until I go the one that corresponded with the above decimal)



That is as far as I got and I am probably wrong.

Then someone will post the real answer and it will be clear to me!!!!

ETA: Wow--I got the same answer as everyone else.

I agree with you. The ratio is 7D/8R.

 

[lulugirl]

I won't even try to solve it, my 7yr. old has better math skills than I do.

 

[disneyeveryyear]

thanks guys!, not sure why this was so much trouble.