this is a two part question.
Dylan owns a bakery where she sells cakes for $20 each, pies for $15each,and doughnuts for $2 each. Her total income,t, can be computed using the equation t=15p+2d+20c
1) solve this equation for d
t=15p+2d+20c
-15p -15p
t -15p=2d+20c
-20c -20c
t-15p-20c=2d
now divide each side by2
d=t-15p-20c/2 I stopped here but my friend went one further and did
d=t-15p/2-10c
Which is correct?
2) part 2 says Last week Dylan's total sales were $1225 not including sales tax. She knows that she sold 32 cakes and 15pies. Use the equation from
part 1 to determine how many donuts were sold last week.
d=t-15p-20c/2
d=1225-15(15)-20(32)/2
d= 1225-225-640/2
d=360/2
d=180 my friend thought this was the answer
I thought the answer was 180/2= 90
I said 90 because each was $2 so you had to divide the answer by 2 giving you 90
Can you tell me who is correct for part 1 & 2.
Thank you so much for helping us
d=t-15p-20c/2
is correct if you use some parentheses
d=(t-15p-20c)/2
now you won't make the mistake your friend did; you will get
d = t/2 - 15p/2 - 10c
on the other hand, if your friend got
d = (t-15p)/2 - 10c
then that's ok
On #2, d=180 is correct. That answer already includes the division by 2.
I mean, the equation said d=..., not 2d=... The answer you got was in fact d.
If you're not convinced, add it up:
180(2)+15(15)+20(32) = 360+225+640 = 1225
Thank you for explaining it. When I see Steve as the person answering my question I know I will get an explanation and I will understand everything better afterwards.
Thank you so much
aww shucks.
Reiny is also very good at explaining the solutions he provides.
Reiny and ms sue are also very good.
For part 1, the correct solution is:
d = (t - 15p - 20c)/2
So your friend went one step further and simplified it correctly. The equation your friend wrote, d = t - 15p/2 - 10c, is the correct simplification of the equation.
For part 2, let's substitute the given values into the equation:
d = 1225 - 15(15) - 20(32)/2
Now we can simplify the equation:
d = 1225 - 225 - 640/2
d = 1225 - 225 - 320
d = 680 - 320
d = 360
Therefore, the correct answer for the number of donuts sold last week is 360.
Your friend's answer of 180 is incorrect because they made a mistake in the computation. You are correct in saying that each donut is sold for $2, but the equation already takes that into account when dividing by 2. So there is no need to divide the answer by 2 again.
Therefore, for part 1, your friend is correct, and for part 2, the correct answer is 360, not 90.