Q&A - PSLE Math

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MathIzzzFun, thank you 

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Hi, can someone pls help with these qns:


1) Kelly and Tom started walking from the same starting point but in the opposite directions along a straight path. Kelly’s average speed was 4 km/h faster than Tom’s. After walking for 3 hrs, they were 40 km apart. What was kellly’s average speed?

2) in a class library, there are some fiction and non fiction books. If we remove 1 non fiction book from the library, 1/7 of the remaining books are non fiction books. If, instead of removing 1 non fiction book, we remove 2 fiction books from the library, then 1/5 of the remaining books are non fiction books. How many books are there in the class library? Thanks.

[The Right Equation]

YumYum:

Hi, can someone pls help with these qns:


1) Kelly and Tom started walking from the same starting point but in the opposite directions along a straight path. Kelly's average speed was 4 km/h faster than Tom's. After walking for 3 hrs, they were 40 km apart. What was kellly's average speed?

http://i43.tinypic.com/51vrd1.jpg\">

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The Right Equation Education:

YumYum:

Hi, can someone pls help with these qns:


1) Kelly and Tom started walking from the same starting point but in the opposite directions along a straight path. Kelly's average speed was 4 km/h faster than Tom's. After walking for 3 hrs, they were 40 km apart. What was kellly's average speed?

http://i43.tinypic.com/51vrd1.jpg\">

Hi, erm... do you mind explaining why do you take 6x + 12 = 40 as 40 is the distance apart and not distance travelled? tyvm.

[The Right Equation]

since tom & kelly are travelling in opposite direction and their distance apart after 3 hours add up to 40km, it means both their distances travelled in 3 hours add up to the 40 km.


hence the equation formed is as such:

(kelly’s dist in 3 hours) + (tom’s dist in 3 hours) = 40 km

[YumYum]

Ok, got it, DC missed the key point on "same starting point", thks!

[The Right Equation]

YumYum:

Hi, can someone pls help with these qns:


2) in a class library, there are some fiction and non fiction books. If we remove 1 non fiction book from the library, 1/7 of the remaining books are non fiction books. If, instead of removing 1 non fiction book, we remove 2 fiction books from the library, then 1/5 of the remaining books are non fiction books. How many books are there in the class library? Thanks.

this qn is slightly higher order, and involves forming & solving equations, using simple substitution.

http://i40.tinypic.com/2i6as0.jpg\">

[justcoping]

Hi

I am stuck at this question from the PSLE booklet. I’ve been staring at it for the last one hour and am still unable to solve it. Please help! Not sure if anyone posted it here before. My apologies if the solution had been posted before.

Qn: Faizal and Gary ran in a race. When Gary had completed the race, Faizal had only run 5/8 of the distance. Gary’s speed was 75m/min faster than Faizal’s speed. Both of them did not change their speeds throughout the race.
What was Faizal’s speed in m/min?

[The Right Equation]

justcoping:

Hi

I am stuck at this question from the PSLE booklet. I've been staring at it for the last one hour and am still unable to solve it. Please help! Not sure if anyone posted it here before. My apologies if the solution had been posted before.

Qn: Faizal and Gary ran in a race. When Gary had completed the race, Faizal had only run 5/8 of the distance. Gary's speed was 75m/min faster than Faizal's speed. Both of them did not change their speeds throughout the race.
What was Faizal's speed in m/min?

http://i41.tinypic.com/292pjja.jpg\">

[justcoping]

The Right Equation Education:

justcoping:

Hi

I am stuck at this question from the PSLE booklet. I've been staring at it for the last one hour and am still unable to solve it. Please help! Not sure if anyone posted it here before. My apologies if the solution had been posted before.

Qn: Faizal and Gary ran in a race. When Gary had completed the race, Faizal had only run 5/8 of the distance. Gary's speed was 75m/min faster than Faizal's speed. Both of them did not change their speeds throughout the race.
What was Faizal's speed in m/min?

http://i41.tinypic.com/292pjja.jpg\">

Wow! That's fast. Thanks.