Q&A - PSLE Math

[MathIzzzFun]

Winx5015:

Hi, need help for the following questions.


(1) If Ahmad and Ben work together, they can complete a job in 8 days. If Ahmad were to work alone for 2 days, he can finish 3/20 of the job in 2 days. How many days will Ben take to complete the job if he were to work alone?

Thanks:)

Q1.

Ahmad & Ben --> 8 days ---> 20 units of work
Ahmad --> 2 days --> 3 units of work
Ahmad --> 8 days --> 12 units of work
Ben --> 8 days --> (20-12) = 8 units of work
Ben --> 20 units of work --> 20 days
Ben will take 20 days to complete the work on his own.

cheers.

[MathIzzzFun]

Winx5015:

Hi, need help for the following questions.


(2) Steve and Huiling took part in a walkathon which started at 6.30am. Steve's average speed was 15 m/min faster than Huiling. Both of them did not change their speed throughout the walkathon. When Steve reached the finishing line after 40 minutes, Huiling had only walked 8/9 of the distance.
(a) What time was it when Huiling completed the walkathon?
(b) Find Steve's average speed for the walkathon in m/min.

Thanks:)

Q2.

when Steve reached finishing line,
distance covered by Steve : Huiling --> 9 : 8
time ratio, Steve : Huiling --> 8:9
Time taken by Huiling to reach finish line = 9/8 x 40 min = 45 min
6.30 am + 45 min --> 7.15 am
Huiling reached the finish line at 7.15 am

Steve's speed: Huiling's speed = 9 : 8
Steve's speed = 9 x 15 m/min = 135 m/min

cheers.

[MathIzzzFun]

Winx5015:

Hi, need help for the following questions.



(3) At a concert, tickets were sold at $12, $30 and $50. The sales of $12 tickets made up 25% of the total amount of money collected. The sales of $30 tickets made up 60% of the total amount. given that 5 more $12 tickets were sold than the $30 tickets, how many $50 tickets were sold?

Thanks:)

Q3 - this was discussed on pg 697 --> http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=6960

cheers.

[MathIzzzFun]

Winx5015:

Hi, need help for the following questions.


(4) At a funfair, the children can choose to ride on the Merry-Go-Round or the Train or both with their coupons. 7/10 of the children chose the Merry-Go-round, 45% chose to ride on the Train, and 10% of the children did not take any of the two rides. A total of 75 children went for both rides.
(a) How many children took ONE ride at the Merry-Go-Round only?
(b) How many children did not take any rides?

Thanks:)

Q4
None of the rides --> 10%
Merry-Go-Round --> 70%
Train ONLY --> 100% - 10%- 70% = 20%
Train --> 45%
Merry-Go-Round & Train --> 45% - 20% = 25%
a) Merry-Go-Round ONLY --> 70% - 25% = 45%

b) 25% --> 75
10% --> 30
30 children did not take any rides

cheers.

[whitety]

MathIzzzFun:

peggy:

Please help :

2.an equal number of men and women were at a party. The ratio of the number of woman who wore watches to the number of men who wore watches was 3:11. The ratio of the number of women to the number of men who did not wear watches was 5:3.

A. Find the ratio of the number of women who wore watches to the number of women who did not wear watches.

Many thanks.

Q2.
a)
wearing watches, women : men = 3 : 11 (difference of
not wearing watches, women : men = 5:3 (difference of 2)
--> difference must be the same since equal number of men and women

wearing watches, women : men = 3u : 11u
not wearing watches, women : men = 20u : 12u
women wearing watches : women not wearing watches = 3:20



Hi MathIzzzFun,

wearing watches, women : men = 3u : 11u need to x4? = 12u : 44u
not wearing watches, women : men = 20u : 12u
women wearing watches : women not wearing watches = 3:20
-> then answer will be 3:5, is my understanding wrong ?

Thanks!

[MathIzzzFun]

whitety:

MathIzzzFun:

[quote=\"peggy\"]Please help :

2.an equal number of men and women were at a party. The ratio of the number of woman who wore watches to the number of men who wore watches was 3:11. The ratio of the number of women to the number of men who did not wear watches was 5:3.

A. Find the ratio of the number of women who wore watches to the number of women who did not wear watches.

Many thanks.

Q2.
a)
wearing watches, women : men = 3 : 11 (difference of
not wearing watches, women : men = 5:3 (difference of 2)
--> difference must be the same since equal number of men and women

wearing watches, women : men = 3u : 11u
not wearing watches, women : men = 20u : 12u
women wearing watches : women not wearing watches = 3:20



Hi MathIzzzFun,

wearing watches, women : men = 3u : 11u need to x4? = 12u : 44u
not wearing watches, women : men = 20u : 12u
women wearing watches : women not wearing watches = 3:20
-> then answer will be 3:5, is my understanding wrong ?

Thanks![/quote]hope this MD helps...

http://i48.tinypic.com/2qledjr.png\">

cheers.

[whitety]

Hi MathIzzzFun,


Thank you very much!

[Winx5015]

Millions thanks to MathIzzzFun for solving my problems.


Have a nice day

[mummyL]

Mr Tok left for Town A for Town B at 11.30am. He travelled at an average speed of 75km/h. At 12.15pm, Ms Selva left Town A for Town B, travelling on the same route at an average speed of 100km/h.

(a) At what time would Ms Selva overtake Mr Tok? Ans 2.30pm
(b)After Ms Selva had overtaken Mr Tok, she took another 2 hours to reach Town B.What
was the distance between Town A and Town B? Ans 425km

[tianzhu]

mummyL:

Mr Tok left for Town A for Town B at 11.30am. He travelled at an average speed of 75km/h. At 12.15pm, Ms Selva left Town A for Town B, travelling on the same route at an average speed of 100km/h.

(a) At what time would Ms Selva overtake Mr Tok? Ans 2.30pm
(b)After Ms Selva had overtaken Mr Tok, she took another 2 hours to reach Town B.What
was the distance between Town A and Town B? Ans 425km

Hi

Your question is pretty similar to the earlier one posted by peggy.

Please refer to page 700 of this thread.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=6990

Distance travelled by Mr Tok from 1130 to 1215 ------- ¾*75 --------- 56.25

100 – 75 ------- 25

56.25/25 ------- 2h 15 minutes

From 1215, add 2h 15 minutes

Mr Selva overtakes Mr Tok at 2.30 pm

Mr Selva travelled for 4h 15 minutes (2h 15 minutes + 2h)

Distance between A and B ------ 4.25*100 ------- 425 km

Best wishes