Q&A - PSLE Math

[MathIzzzFun]

pixiedust:

This is not a maths problem but I need help to understand/explain the equal concept, units method :


The method is to find a common multiple by making the numerators of both fractions the same. why ? Instead of just memorizing the steps, I want to know why is it if the numerator are the same, the denominators are the total units?

1/2 of apples = 3/4 of pears
3/6 of apples = 3/4 of pears
Total fruits 4+6=10 units <---- why ?

Hi pixiedust,

hope this illustration will help


http://postimage.org/image/7fr1mi78/

cheers.

[chrisu]

Pls help;


Tony had 15% more 50c coins than 20c coins. If there were 6 more 50c coins than 20c coins, how much money did Tony have?

Note : This question is from My Pals are here, Maths Test 6 pg.70 Q40. My DD is $31 but teacher said wrong. No answer given yet.

[tianzhu]

chrisu:

Pls help;


Tony had 15% more 50c coins than 20c coins. If there were 6 more 50c coins than 20c coins, how much money did Tony have?

Note : This question is from My Pals are here, Maths Test 6 pg.70 Q40. My DD is $31 but teacher said wrong. No answer given yet.

Hi

I did a quick check and I think $31 is correct.

Best wishes

[chrisu]

Thanks. I also got the same $31. Unless the 15% is of 50c and 20c altogether.

tianzhu:

chrisu:

Pls help;

Tony had 15% more 50c coins than 20c coins. If there were 6 more 50c coins than 20c coins, how much money did Tony have?

Note : This question is from My Pals are here, Maths Test 6 pg.70 Q40. My DD is $31 but teacher said wrong. No answer given yet.

Hi

I did a quick check and I think $31 is correct.

Best wishes

[tianzhu]

pixiedust:

Tianzhu, your illustrations are really really nice!

Hi pixiedust

Good Morning.

You're welcome.

Best wishes

[pixiedust]

Thank you, mathizzzfun. This morning when I look at it again, I got it. So simple yet I took so long :oops: Thanks again.

[chrisu]

Just as I expected, the answer is $14.90 given by the teacher. The teacher will explain tomorrow.

chrisu:

Thanks. I also got the same $31. Unless the 15% is of 50c and 20c altogether.

tianzhu:

[quote=\"chrisu\"]Pls help;

Tony had 15% more 50c coins than 20c coins. If there were 6 more 50c coins than 20c coins, how much money did Tony have?

Note : This question is from My Pals are here, Maths Test 6 pg.70 Q40. My DD is $31 but teacher said wrong. No answer given yet.

Hi

I did a quick check and I think $31 is correct.

Best wishes

[/quote]

[MathIzzzFun]

pixiedust:

Thank you, mathizzzfun. This morning when I look at it again, I got it. So simple yet I took so long :oops: Thanks again.

Hi pixiedust,

you are welcome :lol: it's normal for us to get \"choked\" - I too get choked at times.. this forum is great cos it offers various approaches to solving the same problem.

cheers.

[BlueBells]

chrisu:

Pls help;


Tony had 15% more 50c coins than 20c coins. If there were 6 more 50c coins than 20c coins, how much money did Tony have?

Note : This question is from My Pals are here, Maths Test 6 pg.70 Q40. My DD is $31 but teacher said wrong. No answer given yet.

Problem with image, so here goes my workings :


15% => 6 more 50c coins, so if total number of coins =100%

Then, Tony would have 65% 50c coins and 35% 20c coins

Since
15% = 6 more 50c coins,
85% = (6 x 85) / 15 = 34 coins

34 / 2 = 17 50c coins and 17 20c coins

Thus, Tony would have
[(17 + 6) x $0.50] + (17 x $0.20) = $14.90

[tianzhu]

chrisu:

Just as I expected, the answer is $14.90 given by the teacher. The teacher will explain tomorrow.

Hi

Interesting, please share the teacher’s solution after you receive it.

If the question is worded exactly like what it’s described, the answer is $31.

Best wishes