QUESTION 1
A man bought a laptop and a digital camera. He paid $2400 in all.If the digital camera cost 20% of the cost of the laptop,how much did he pay for the laptop?

QUESTION 2
In a collection of red,blue and yellow balls,there are 500 balls altogether.35% of the balls are red,25% of the balls are blue and the rest of the balls yellow.If 100 blue balls are added to the collection,how would the overall percentages of the different colored balls be changed?What are the new percentages?Round off your answers to 1 decimal place.

MY ANSWER TO QUESTION 2

35% OF RED BALLS = 35 × 500 = 175 red balls
100
25% OF BLUE BALLS= 25 × 500 = 125 blue balls
100

40% OF YELLOW BALLS = 40 × 500 = 200 yellow balls
100

125 blue balls + 100 = 225 blue balls

175 × 100% = 29 1 %
600 6

225 × 100% = 37 1 %
600 2

200 × 100% = 33 1 %
600 3

OH MAN! MY ANSWER WAS A DRAG TO WRITE.......

Is my answer correct?

It's probably easy for you, too. You are just confusing yourself. I see from your other problem workings that you are rather haphazard about it. Be more deliberate and organized. I'll do the whole thing for free since you very niclely showed your work on the other one.

Rule #1 - Name Stuff!
Question #1 - Name What?
Answer #1 - What does it want? Name that.

"how much did he pay for the laptop?"

Perfect

L = How much he paid for the laptop

There is also a camera in there. Fine.

C = How much he paid for the camera.

Now translate...

"He paid $2400 in all"

Fine.

L + C = $2400 <== Make sure you see how this was translated.

"the digital camera cost 20% of the cost of the laptop"

C = (20%)*L <== Make sure you see how this was translated.
or
C = L*(0.20) <== You should be able to do such conversion in your sleep.

Now solve, oftentimes by simple substitution.

L + C = $2400
Substitute
L + (L*(0.20)) = $2400
Combine like terms
L(1.20) = $2400
Divide
L = $2400/1.20
L = $2000

C = L*(0.20) = ($2000)*0.20 = $400

Check

L + C = $2400
Substitute
$2000 + $400 = $2400 -- Perfect

One more thing. Go REread the question and make sure we answered everthing it wanted. If we answered a little more than it asked, that might be fine. You would want to avoid that on a timed examination, but here it is good practice.

Notice how organized this is. Thoughts go down on the paper. Do NOT try to do it all in your head. Do NOT skip steps. Do NOT give in to the temptation to avoid writing each step and each thought. Let the notation help you.

Show us another one with some process improvements.

By the way,you got QUESTION 2 WRONG.

HERE'S MY ANSWER

Cost of laptop= 80 over 100 X $2400 = $1,920

And by the way,the digital camera is $480,not $400!

And by the way, your post is insulting and has been reported to the moderators. By the way.

__________________
There are two things you should never try to prove: the impossible and the obvious.

The greater danger for most of us lies not in setting our aim too high and falling short; but in setting our aim too low and achieving our mark. (Michelangelo Buonarroti)

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, or

So this is wrong because the camera cost 20% or the cost of the laptop, not 20% of the total cost of the camera and laptop.

So lets see TKH is correct and you are wrong, unless you asked the wrong question.

RonL

__________________
Truth does not change because it is, or is not, believed by a majority of the people.

Giordano Bruno