Answer:
Step-by-step explanation:
You have the right numbers, but the wrong accounts.
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Let x represent the amount invested at 8% (the highest rate). Then the total interest is ...
.08x +.03(3000 -x) = .04(3000)
.05x = .01(3000) . . . . subtract .03(3000)
x = 3000/5 = 600
Matthew invested $600 at 8%, $2400 at 3%.
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<em>Comment on checking your answer</em>
You may notice that the overall interest rate is 4%, closer to 3% than to 8%. That means more of the money must be invested at 3% than at 8%.
We have 3 people: Paul, Daniel and Patricia. Let each name denote that person’s current age in years. Remember that % is the symbol for 1/100.
PAUL: (#A) Paul = Patricia – 2
DANIEL:
(#B) Daniel = 125% * Patricia = 125 * (1/100) * Patricia = 1.25 * Patricia
(#C) Ten years ago, Daniel’s age at that time would have been Daniel’s current age – 10. IE “Daniel – 10”.
Ten years ago, Patricia’s age at that time would have been Patricia’s current age – 10. IE “Patricia – 10”.
Ten years ago, Daniel’s age at that time (IE Daniel – 10) was 50% greater than Patricia’s age at the time (Patricia – 10).
IE
Daniel – 10 = 150% * (Patricia – 10)
Daniel – 10 = 1.50 * (Patricia – 10)
Daniel – 10 = 1.50 * Patricia – 1.50 * 10
Daniel – 10 = 1.50 * Patricia – 15
Daniel = 1.50 * Patricia – 15 + 10
Daniel = 1.50 * Patricia – 5
So now we have 3 equations in 3 unknowns:
(A) Paul = Patricia – 2
(B) Daniel = 1.25 * Patricia
(C) Daniel = 1.50 * Patricia – 5
Solve equations B & C simultaneously
1.25 * Patricia = 1.50 * Patricia – 5
1.25 * Patricia – 1.50 * Patricia = – 5
– 0.25 * Patricia = – 5
Patricia = (– 5) / (– 0.25)
Patricia = + 20
So now we can write the 3 people’s ages:
(a) Patricia = 20
(b) Paul = Patricia – 2 = 20 – 2 = 18
(c) Daniel = 1.25 * Patricia = 1.25 * 20 = 25
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<span>Finally, we check our solution against the original question. </span>
Paul is two years younger than Patricia. ……… 20 – 2 = 18 ✔
Daniel is 25% older than Patricia. ……… 25 = 125% * 20 ✔
Ten years ago, Daniel was 50% older than Patricia. 25 – 10 = 150% (20– 10) ✔
Hope that helped :)
Answer:
Step-by-step explanation:
When dividing fractions, the formula is simple: Keep Flip Change (KFC)
So keep 
change your division sign to a multiplication sign, and flip 
so it becomes 
.
·=
Then you need to reduce your fraction to simplest form.
Answer:
20.36
Step-by-step explanation:
The area of the whole circle is pi*3.6^2 = 40.715 (rounded). However, the shaded portion is only half of the circle, since the arc is 180 degrees, so we divide this by 2 to get about 20.36.
The average would be the total amount divided by the 2 groups, so the answer would be 37.5 years old.
