Q&A - PSLE Math

[Vanilla Cake]

Hi MathIzzzFun,


There are 2 different answers given for these 2 questions from 2011 CHIJ St. Nic P6 Prelim Maths. Could you pls confirm the correct answers? No need to type out the worked solutions for them.
TIA for your time plus effort & cheers.

Paper 2 Q3
Sheela was 25 min late for a movie. She was at the cinema at 8.15 p.m. If the duration of the movie was 137 min, at what time did the movie end?
Leave your answer in the 24-hour clock.
2 different answers were given: 2107 or 2207

Paper 2 Q18
A rectangular tank measuring 40 cm by 30 cm by 40 cm was 1/6 filled with water. At 0930 h, Tap X with water flowing out at a rate of 3 l per minute was turned on. At 0932 h, Tap Y was turned on to drained water out of the tank at a fixed rate. At 0943 h, the tank was 75% filled with water. At what time would the tank be filled to the brim?
2 different answers were given: 0949 h or 0954 h

[MathIzzzFun]

Vanilla Cake:

Hi MathIzzzFun,


There are 2 different answers given for these 2 questions from 2011 CHIJ St. Nic P6 Prelim Maths. Could you pls confirm the correct answers? No need to type out the worked solutions for them.
TIA for your time plus effort & cheers.

Paper 2 Q3
Sheela was 25 min late for a movie. She was at the cinema at 8.15 p.m. If the duration of the movie was 137 min, at what time did the movie end?
Leave your answer in the 24-hour clock.
2 different answers were given: 2107 or 2207

Paper 2 Q18
A rectangular tank measuring 40 cm by 30 cm by 40 cm was 1/6 filled with water. At 0930 h, Tap X with water flowing out at a rate of 3 l per minute was turned on. At 0932 h, Tap Y was turned on to drained water out of the tank at a fixed rate. At 0943 h, the tank was 75% filled with water. At what time would the tank be filled to the brim?
2 different answers were given: 0949 h or 0954 h

Hi

Paper 2 Q3 - 2207
Movie started at 8.15pm - 25min = 7.50pm or 1950 h
137 min = 2h 17 min, movie ended at 1950 + 2h 17min = 2207 h

Paper 2 Q18 - 0949 h
check points:
Full volume = 48l
0930 h, volume of water in tank = 8l
0932 h, volume of water in tank = 14l (+ 3l/min x 2min = 6l)
0943 h, volume of water in tank = 36l (increase of 22l in 11 min ie + 2l/min, so tank Y draining at 1l/min)

Volume left to fill = 12l, 12l / 2l/min = 6min

0943 h + 6 min = 0949 h

cheers.

[MathIzzzFun]

looking4Tutor:

Thank you very much, MathIzzzFun and tianzhu.

u r welcome

cheers.

[Tang]

Despair:

Sorry for the trouble, five tough questions,


1. Mr Foo started to travel from Town P to Settlement Q on his limousine at 10 30 at an average speed of 48km/h. After taking a rest for 45 min, he continued travelling from Settlement Q to City R at an average speed that was 1.5 times his earlier average speed. He arrived at City R at 15 00. Given that the distance between Settlement Q and City R is 30 km less than the distance between Town P and Settlement Q, find the distance between Town P and City R.

Hi,

Time from 1030 to 1500 = 4 1/2 h

4 1/2 - 45/60 = 3 3/4 h

1.5 = 3/2

30/48 = 5/8 h

[ ][ ][ ][5/8][ ][ ]

5 u --> 3 3/4 - 5/8 = 3 1/8 h
3 u --> 3/5 x 3 1/8 = 1 7/8 h

48 x 1 7/8 = 90 km

90 x 2 + 30 = 210 km

[tianzhu]

Hi


Hope this helps.

Best wishes.

http://farm7.static.flickr.com/6063/6139917034_a6c214361a_z.jpg\">

[ms_lim]

MathIzzzFun:

ivanhoo99:

Hi pls help


Mr Tan drove from city X to city Y.At the same time,Mr Koh drove from city Y to city X.They passed each other 64 km away from city Y and continued their journeys. They made a u-turn upon reaching their destinations so that they could return to their own cities. They passed each other again 52 km away from city X.. Find the distance between the two places when they met each other.

This question has been posted much earlier but can't seem to find the solution..

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

[MathIzzzFun]

ms_lim:

MathIzzzFun:

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

Hi

After they first meet at A, Mr Koh travelled from A-X-B and Mr Tan travelled from A-Y-B, and the total distance travelled ie A-X-B + A-Y-B, is 2XY

It is assumed that both Mr Tan and Mr Koh travelled at constant speed throughout their journeys, Mr Koh travelled 64km in the first part of journey (total distance =XY), and since total distance travelled in the 2nd part of the journey is 2XY, and he would travel 2 x the distance which is 2 x 64km

cheers.

[ms_lim]

MathIzzzFun:

ms_lim:

[quote=\"MathIzzzFun\"]

Hi

http://www.flickr.com/photos/62167097@N02/6085706330/in/photostream

cheers.

Dear MathIzzzFun, can you help to explain why the distance travelled by Mr Koh from A to B = 2 x 64km = 128km?

Hi

After they first meet at A, Mr Koh travelled from A-X-B and Mr Tan travelled from A-Y-B, and the total distance travelled ie A-X-B + A-Y-B, is 2XY

It is assumed that both Mr Tan and Mr Koh travelled at constant speed throughout their journeys, Mr Koh travelled 64km in the first part of journey (total distance =XY), and since total distance travelled in the 2nd part of the journey is 2XY, and he would travel 2 x the distance which is 2 x 64km

cheers.[/quote] :thankyou: MathIzzzFun for your detailed explanation.

[Andrew Lee]

Hi


please clean up the pic.. difficult to figure out where are the x,y, z... if these are lying on the same straight line then there is no definite answer for x,y,z (y+z=180)... because the line DEF is not anchored.

cheers.[/quote]

So sorry. I already clean up the pic, hope you can see it

http://i56.tinypic.com/hvdro2.jpg\">

[Andrew Lee]

http://i54.tinypic.com/rcshzd.jpg\">[/quote]


Hi

please check question ...

http://i52.tinypic.com/30ug1e0.jpg\">

It is \"a\"..but then how to get (a) answer?
Hi

the question is flawed.

cheers.[/quote]

Can explain why which part of this question is flawed?