SOLUTION: The weight of sugar used to bake a cake was 3/5th the weight of flour used. The weight of butter used was 5/6th the weight of sugar used. a. Find the ratio of the weight of sug

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The weight of sugar used to bake a cake was 3/5th the weight of flour used. The weight of butter used was 5/6th the weight of sugar used. a. Find the ratio of the weight of sug      Log On


   



Question 1038089: The weight of sugar used to bake a cake was 3/5th the weight of flour used. The weight of butter used was 5/6th the weight of sugar used.
a. Find the ratio of the weight of sugar to the weight of flour to the total weight of the 3 ingredients.
b. If 100g more flour used than sugar, how much butter was used to bake the
cake?

Found 2 solutions by josmiceli, Theo:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = weight of sugar used
Let +b+ = weight of butter used
Let +f+ = weight of flour used
------------------------------
+s+=+%283%2F5%29%2Af+
+b+=+%285%2F6%29%2As+
-------------------
I don't understand (a)
It doesn't seem grammatically correct
(b)
+f+=+s+%2B+100+
+f+=++%283%2F5%29%2Af+%2B+100+
+%282%2F5%29%2Af+=+100+
+f+=+%285%2F2%29%2A100+
+f+=+250+ g
---------------
+250+=+s+%2B+100+
+s+=+150+
and
+b+=+%285%2F6%29%2As+
+b+=+%285%2F6%29%2A150+
+b+=+25%2A5+
+b+=+125+
125 g of butter was used

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
s = weight of sugar
f = weight of flour
b = weight of butter.
t = weight of all 3 ingredients.

s = 3/5 * f
b = 5/6 * s = 5/6 * 3/5 * f = 15/30 * f = 1/2 * f

you have:

s = 3/5 * f
b = 1/2 * f

t = s + f + b = 3/5 * f + f + 1/2 * f = 6/10 * f + 10/10 * f + 5/10 * f = (6+10+5)/10 * f = 21/10 * f

you have:

s = 3/5 * f
b = 1/2 * f
t = 21/10 * f

from t = 21/10 * f, solve for f to get f = 10/21 * t

the ratio of sugar to flour is 3/5.
the ratio of flour to total is 10/21.

since 3/5 is equivalent to 6/10, you get:
the ratio of sugar to flour is 6/10
the ratio of flour to total is 10/21.

this means the ratio of sugar to flour to total is 6:10:21.

the total number of parts is 21.
6 of them are sugar.
10 of them are flour.
5 of them have to be butter.

since b = 1/2 * f, this makes sense.

since 100 grams more of flour was used than sugar, you get:
f = s + 100
this means that f - s = 100
since s = 3/5 * f, this means that f - 3/5 * f = 100
simplify to get 2/5 * f = 100
solve for f to get f = 5 * 100 / 2 = 250.

*****THIS IS WHERE I SCREWED IT UP PREVIOUSLY
*****THANKS FOR LETTING ME KNOW.

since f = s + 100, you get s = f - 100 = 150.

you wind up with:

f = 250
s = 150

since b = 5/6 * s, then b = 750 / 6 = 125

you now have:
s = 150
f = 250
b = 125

since t = s + b + f, then t = 525.

150 grams of sugar and 250 grams of flour and 125 grams of butter were used to make the cake.

s = 3/5 * f becomes 150 = 3/5 * 250 which becomes 150 = 150.
this confirms the relationship between butter and flour is correct.

b = 5/6 * s becomes 125 = 5/6 * 150 which becomes 125 = 125.
this confirms the relationship between butter and sugar is correct.

we had a ratio of s:f:t = 6:10:21

the ratio of s:f:t in grams of each is 150:250:525

if you divide each of the grams by 25, you get a ratio of 6:10:21 which confirms the ratios are correct.